IRENE Space Radiation Modelling and Data Analysis Workshop 2019

29 May 2019, 11:00 → 31 May 2019, 20:00 Europe/Athens

Sykia, Peloponnese, Greece

Ingmar Sandberg (Space Applications & Research Consultancy (SPARC)), Paul O'Brien (Aerospace Corporation), Piers Jiggens (ESA/ESTEC)

Overview

We are pleased to announce the IRENE Space Radiation Modelling and Data Analysis Workshop 2019, organized by:

• AE-9/AP-9/SPM Technical Team
• European Space Agency (ESA)
• Space Applications & Research Consultancy (SPARC) [local organization]

The workshop brings together experts in the field of space radiation data analysis and model development in order to:

• Prioritize future activities
• Identify needs and open issues
• Intensify European and International collaboration
• Present modelling developments relevant to space radiation environment

The sessions of the meeting will include the following topics:

• Data assimilation
• Data sharing & new datasets
• Long term simulation of the global RB environment
• Solar Energetic Particle (SEP) environment modelling
• Combining models of different radiation and plasma environments
• Collaboration schemes for developing future work
• User accommodations: release versioning & effects calculations

We are glad to announce that more than 25 attendees have confirmed their participation.

Wednesday 29 May

13:00 → 13:30 Conference: Registration and Welcome

13:00 Introduction

Overview of the workshop purpose and goals. Some practical information

Speakers: Dr Piers Jiggens, Dr PAUL OBRIEN (The Aerospace Corporation), Ingmar Sandberg

Introduction.pptx

13:15 Multi-model framework of the near-Earth radiation environment

The European Space Radiation Environment Modelling system (ESPREM) is a modular framework that attempts to capture the radiation in the near-Earth environment from various sources and provide estimates for its effects. It is composed of models for the trapped radiation inside the Earth's Radiation Belts, i.e. the American AE9/AP9/SPM & the European Trapped Energetic Particle Environment Model (TREPEM) as well as its counterpart from solar and galactic sources, as described by the Virtual Enhancements – Solar Proton Event Radiation (VESPER) and Matthiä's DLR GCR models. Especially for the latter two sources, the system implements the Magnetospheric Shielding Model (MSM) to account for the shielding effect of the Magnetosphere. The environment model outputs are coupled with state-of-the-art radiation effects tools (e.g. MULASSIS, IRONSSIS and MCICT) to estimate internal charging, ionising and non-ionising dose and single event effects. The probability distributions of the radiation effects - resulted from different sources - are merged statistically assuming various degrees of inter-correlations and provide as an output the confidence levels for the effects along a given satellite orbit. As a result, the developed system captures the net effect from all radiation sources providing a single framework for the design and evaluation of future missions.

Speaker: Mr Constantinos Papadimitriou

ESPREM - ecIRENE 2019.pdf

13:30 → 14:50 Datasets & Data Sharing: 1

13:30 Angular proton distributions measured by Proba-V/EPT and their comparison to AP8 and IRENE/AP9

During the Proba-V mission (7 May 2013 - present) two campaigns were led to measure angular distributions of protons at various positions in the South Atlantic Anomaly (SAA): 1st from June 2013 - January 2014 and 2nd from December 2017 - February 2018. The measurements were realized through rotation of the satellite, to adjust the EPT viewing direction with respect to the magnetic field, before the satellite enters the targeted bins (three bins were selected).
The objective of the off-pointing measurements in 2017 was twofold: 1) to better characterize the performances of the instrument after its recalibration in summer 2014, and 2) to extend the angular distribution study to regions of higher L and B but without approaching the boarder of the SAA where atmospheric effects, like east-west asymmetry, are observed.
During the presentation, the data analysis will be exposed and for the three position bins under investigation, comparison with AP8 and IRENE/AP9 will be shown and differences discussed.
Additionally, new SSA Proba-V/EPT radiation modelling linked products will be presented.

Speaker: Dr Stanislav Borisov (UCLouvain - CSR)

IRENE_WSmai2019_v0.pptx

13:50 High-energy trapped protons measured by PAMELA

The PAMELA mission has recently measured the fluxes of geomagnetically trapped protons with energy between 80 MeV and a few GeV at low Earth orbit (350-610 km). Data were analyzed in the frame of the adiabatic theory of charged particle motion in the geomagnetic field. Flux properties were investigated in detail, providing a full characterization of the proton radiation in the South Atlantic Anomaly region, including locations, energy spectra, and pitch angle distributions. PAMELA observations significantly improve the description of the Earth's radiation environment at low altitudes and high energies, placing important constraints on the trapping and interaction processes.

Speaker: Dr Alessandro Bruno (NASA/GSFC)

High-energy trapped protons 
measured by PAMELA

14:10 High resolution electron and proton fluxes from SREM data

An inverse method for the calculation of particle fluxes from space radiation monitor data is presented. The GenCORUM (Genetic Correlative Unfolding Method) employs tools from the fields of Artificial Intelligence and Machine Learning and manages to provide physically meaningful differential spectra of proton and electron fluxes in wide energy ranges with high energy resolution. Results are shown from the analysis of data from ESA’s Standard Radiation Environment Monitor (SREM) on board the INTEGRAL mission. Of particular interest is the derivation of electron fluxes in energies E ≥ 2 MeV which show good agreement with data from the Magnetic Electron Ion Spectrometer (MagEIS) and the Relativistic Electron Proton Telescope (REPT) which are scientific instruments on board the Van Allen Probes mission.

Speaker: Dr Sigiava Aminalragia-Giamini (SPARC)

Sykia2019_GenCORUM_IREM.pptx

14:30 An overview of the IDP electron detector onboard the DEMETER satellite, data and results

We give a detailed description and the main results of the electron spectrometer placed onboard the Demeter satellite. This detector with a large geometrical factor is aimed to measure electron fluxes close to 90° pitch-angles in the energy range from 70 keV to about 0.8 MeV and to provide information on the electron fluxes between 0.8 and 2.5 MeV. In survey mode, the energy resolution, about 18 keV, and the 128 energy channels allow to obtain insights on the radiation belt structure and dynamics. The data were received from the DEMETER launch in 2004 up to 2011 when the data acquisition was stopped. Some results on the global effect of VLF transmitters and of atmospheric lightnings on radiation belt electrons are presented and discussed as well as global measurements of electron/proton energy structuring associated to drift modulations. We also emphasize some physical and electronics limitations of the measurement such as minimum ionization leading to an overestimation of low energy fluxes and impulses pile-up leading to an apparent increase of the high energy fluxes. We also discuss how the large geometrical factor of the instrument, allowing the detection of low fluxes of electrons and the collection of large count rates has the side effect of increasing the detector dead-time.

Speaker: Dr Jean-André Sauvaud (IRAP/CNRS)

SAUVAUD-IDP.pptx

14:50 → 15:20 Coffee - Wednesday (PM)

15:20 → 17:05 Datasets & Data Sharing: 2

15:20 IPODE : Ionising Particle ONERA DatabasE for Earth’s Radiation Belt Analysis

Satellite engineers, operators, and radiation belt researchers share a common desire to understand and predict the structure and variability of Earth's radiation belts. In the radiation belt community, there is a need for improved scientific understanding of the radiation belts, more accurate dynamic and climatological models, space weather restitution and prediction and a mechanism for more efficient transfer of scientific understanding to the space community. To allow for such advancements to take place, IPODE (Ionising Particle Onera DatabasE) has been developed at ONERA under CNES funding in the frame of the CRATERRE project and EU funding (MAARBLE project). This database is composed of nearly an hundred and a half spacecraft/instrument couples for in-situ Earth’s particle measurements (electron, proton and alpha particles fluxes). The energy range covers roughly ~0.1 keV to few MeV for electrons, ~0.1keV to few 100s MeV for protons. A wide range of orbits are covered: geosynchronous (GEO), global positioning systems (GPS), elliptical (HEO) and low altitude (LEO). Measurements have been and are still gathered through open source data or collaborations between ONERA and international institutions such as Los Alamos National Laboratory (LANL), Aerospace Corporation, JAXA (CNES-JAXA agreement), Moscow State University (MSU) and CONAE (CNES-CONAE agreement). The principal strength of this data base is its global spatial and long time coverage. Moreover, these data are largely analysed and filtered to ensure good quality of measurements and therefore allows to perform radiation belt dynamics survey in near real time and in various regions of the Earth’s space.
This data base has already resulted in the development of models such as IGE 2006, MEO V2, MEO at and nearby Galileo Orbit, OZONE the outer zone electron belt specification model, GREEN, and is used for radiation belt data assimilation and Salammbô code validation.

Speaker: Ms Angélica Sicard (ONERA)

IPODE.pptx

15:40 Internal Charging Current Measurements & Electron Fluxes in Radiation Belts

A review of the Internal Charging Current Measurements from SURF-like units on-board different satellites, such as Galileo, Giove-A, STRV1d and Van Allen Probes will be presented. Methods on the calculation and the validation of derived electron fluxes from these measurements will be demonstrated.

Speaker: Ingmar Sandberg (Space Applications & Research Consultancy (SPARC))

16:00 Sharing data with ODI

ESA's Open Data Interface (ODI) is a data management system built on a MySQL (or MariaDB) SQL database server. The system consists of a server part to handle downloading and storing of time series data files, performing pre- and/or post-processing, and adding geomagnetic coordinates on request. The second component is a collection of client apllications to retrieve data from the database in several programming languages (php, Python, IDL, MATLAB) using a common API syntax. In addition, two Python REST clients are available: one uses the HAPI (Heliospheric API) specification (which is now endorsed by a COSPAR Resolution), the other allows more tailored queries using WHERE and GROUP BY SQL clauses. The ODI server and client packages can be downloaded from the ESA European Space Software Repository (https://essr.esa.int/).

Data sharing is becoming ever more challenging due to growing data volumes, usage of a variety of file formats (e.g. CSV, CDF, netCDF, PDS, FITS), and non-strict implementation of metadata (e.g. ISTP/CDF, SPASE). Data users have to download potentially large data volumes, interpret and/or complement metadata and write data file access routines for each individual dataset.

For many applications, data access using standardised API's to remote data stores would be sufficient, by-passing the need for building local file downloading, interpretation and processing. In addition, all datasets behind an API can be accessed in the same way, which greatly simplifies building local application software. On the data server side, using SQL databases (such as ODI) simplifies data processing and data selection and retrieval, but other solutions can be used as well, as the remote user is only exposed to the API.

Additional aspects of data sharing include:

• making available to the community processed datasets, e.g. after applying de-spiking, cleaning or calibration algorithms;
• selection and processing of data prior to downloading, e.g. data averages, or data binned in geomagnetic coordinates, thus shifting the processing burden to the remote service and vastly reducing download volumes;
• strict adherence to metadata standards;
• facilitation of implementation of mirror sites.

We propose the following topics for the discussion session:

• the HAPI standard does not allow for quantified queries including, for instance, WHERE or GROUP by statements, so it also does not allow to request pre-processing; should the standard be extended, or should existing (e.g. ODI) or future non-HAPI APIs use standardised pre-processing keywords?
• the emerging de facto metadata standard is SPASE (now endorsed by a COSPAR Resolution); however, the metadata dictionary needs to be extended (e.g. for radiation effects quantities), and the ontology currently does not allow easy definitions of non-scalar quantities (e.g. energy spectra);
• releasing post-processed datasets after peer review, and/or inclusion of processing algorithms in data store software.

Speaker: Dr Daniel Heynderickx

Sykia_2019_ODI.pptx

16:20 Discussion

18:00 → 22:00 Conference: Welcome Reception

Thursday 30 May

09:20 → 10:40 Solar Energetic Particle Environment Modelling: 1

09:20 SAPPHIRE: steps forward and current limitations

Two papers presenting the (Solar Accumulative and Peak Proton and Heavy Ion Radiation Environment (SAPPHIRE) model and its implementation we published in 2018. The model deals with short- and long-term SEP environments in a way which is more coherent and consistent than previous approaches. It also leverages extensive work carried out in the processing of data and addressing caveats.
The SAPPHIRE model covers all SEP ions from 0.1 MeV/nuc to 1 GeV/nuc. It also introduces the concept of 1-in-n-year SEP events derived statistically to provide a common baseline for a series of spacecraft.
SAPPHIRE does not present include time series, the high-energy part is extrapolated from 250 MeV/nuc (for protons and lower for heavier ions) and the low-energy peak flux extrapolations (below 5 MeV) are not fully in-line with other in-situ observations.
This talk will briefly present SAPPHIRE and how it can be further evolved to fit in the IRENE framework.

Speaker: Dr Piers Jiggens

SAPPHIRE.pptx

0. Introduction (Multi-model framework of the near-Earth radiation environment

What is motivation for this new framework in the context of Spenvis as a community resource?

1. Datasets and Data Sharing

Cleaned data > back to public?

Cross calibration and analyses > requires agreements. Methodology reported in Final Reports

1.1 Stanislav: Proba-V EPT

reasons for PAD exponent differences (Fischer 12; EPT&AP9 20-24)?

(Added by Eamonn: availability of data? complexity of data processing?)

1.2 Alessandro: Pamela

Particle tracing allows separation of trapped particles vs. untrapped/quasi-trapped 

K, Phi binning plots: why don't they separate the categories more cleanly?; A: ranges of altitudes is analysed blurring the separation

1.3 Sigiava: SREM data analysis

Construct virtual dataset from Integral SREM

SREM generally gives lower e fluxes at conjunctions with VAP

What parameters is genetic algorithm tuning?: A: Flux bins

Questions on quality of response functions and how IREM comparisons can be used; conjunctions allow rescaling; but it could be energy shift

1.4 Jean-Andre: DEMETER IDP

Wisps observed due to ULF transmitter induced e precipitation; Lighting induced precipitation; drift resonances with E field created by ionospheric winds

Data available; free to use for IRENE if desired; Is ESA going to do it?

Corrections and dead-time treatment not included in dataset on line

1.5 Angelica: IPODE

Very large collection of datasets with associated utilities

How many people use the system? Not possible to say

Is it a formal database? A: It's an archive of data files (CDF)

Are there plans to develop it into a formal database? There are development plans in that direction

How many datasets are public and how many not? Not possible to say

Web interface poss.? Not for data download. Only plot the data

Some datasets provided under CNES agreements (e.g. JAXA) and so no right to make available

1.6 Ingmar: Internal Charging

Galileo EMU but also SEDA, Giove-A, Strv-1d, VAP/ERM

IRENE includes current transmission kernels 

Do you have geometry parameters? Yes but they're not public; but design is so simple you can do a simple simulation and its good enough; even 1-D

Have you experimentally tested in an electron beam; differences can be large? A: No but VAP agreement is good so should be OK with the simulation based approach.

1.7 Daniel: ODI Data Sharing

Proprietary Data? A: Data can be flagged as private or put in a separate "private" ODI

Moves to use ODI within IRENE project. Need to capture IRENE needs.

Versioning of data processing? A: Not explicit but can be done by naming

Need a system with easy learning curve; A: it is - has the APIs; can use ASCII

Any plan to harmonise like the Planetary Data System? It was the goal of VIRBO and is effectively being done by CDAWeb.

Anyone can use the ODI to make their own proprietary database system

1.8 DISCUSSION

Data sharing can be risky in that caveats associated with the data must be understood. In some cases its better to keep the data with the originator who will iterate the data with cleaning and reevaluations. Some data processing can be very complex, e.g. the Pamela data and the associated particle tracing to correctly attribute the signal to trapped or untrapped particles. Also Proba-V EPT, CNES SAC  you need to understand the history of operation, detector problems, data download issues, etc.

When making data available it is important to provide the associated metadata and reports that describe in sufficient detail the design and calibration. The user must not interpret the data simplistically but consider carefully (e.g.) field of view, energy bins, contamination, etc.

IPR has to be respected. Some data have restriction due to political or commercial reasons and then correct licensing strategies have to be implemented. This is slow, complex and so costly.

When data are cleaned and de-glitched, they should as a minimum be copied to the originator and if the original data were public, ideally the cleaned version should also be made available if only to avoid multiple parallel efforts on cleaning the same dataset.

ODI allows easy construction of private and public databases composed of data in almost any format and with API for many languages. It is freely available...

The low altitude region is important but problematic. The extrapolation of high altitude data to lower altitudes is difficult so in situ data is preferred.

Here is an opportunity to share LEO data usefully with the IRENE project. But need more LEO missions. Although science focus is on higher altitudes, the PEO orbit has advantages of rapidly transiting L space and capturing dynamics.

What is the motivation for groups to share data? Keeping data allows exploitation for publication and maybe also commercial reasons but sharing allows greater scope for joint publication and allows the value of a group's work to be highlighted to funding agencies and so aid sustained or augmented funding of a group.

Can outputs of physics based models be considered as data and treated in the same way? In principle yes, but here the caveats are probably even more important.

Related to the metadata sharing, there are standards in preparation in the scope of the COSPAR PRBEM to standardize the description of response functions along with other data and metadata formatting standards. https://sourceforge.net/p/irbem/code/HEAD/tree/docs/PRBEM_Response_Format.doc

 

09:40 The VESPER model, a presentation, updates, and future work

The Virtual Enhancements – Solar Proton Event Radiation (VESPER) model is one of the latest efforts in the probabilistic modelling of solar particle radiation. VESPER produces differential proton flux time-series of virtual Solar Proton Events (SPEs) for arbitrary mission durations. These virtual SPEs are constructed by rescaling historical SPEs in a spectrally coherent way. A presentation on the VESPER methodology is made and the approach on current and future improvements and updates is shown and discussed.

Speaker: Dr Sigiava Aminalragia-Giamini (SPARC)

10:00 Time-series SEP simulations and complications

Recently a new SEP probabilistic model, VESPER, was introduced. It makes use of virtual time-series of proton differential intensities of particle events. This is in contrast to previous models like ESP, JPL, the SEPEM/VTM and SAPPHIRE that use peak flux and fluence distributions. Besides, the SEPEM statistical model for interplanetary missions uses the SEPEM helio-radial reference event list for which compound event episodes where splitted into individual SEP enhancements in order to determine the different parent solar activities and to assign a radial dependence of the peak intensity and event fluence based on a set of reference events modelled with the SEPEM/SOLPENCO2 tool. We will discuss here some of the difficulties in deriving either virtual events following the virtual time-series approach, and the assumptions made and complications arising from the splitting of compound-event episodes in the SEPEM/SOLPENCO2 method.

Speaker: Dr Angels Aran (Dep. Quantum Physics and Astrophysics. University of Barcelona)

AAran_IRENE_Sykia.pdf

10:20 Solar energetic particles observed by the PAMELA experiment

The PAMELA satellite experiment has recently provided accurate spectral measurements for 26 solar energetic particle (SEP) events occurring between December 2006 and September 2014. Observations cover the range between 80 MeV and 2 GeV, bridging the low-energy measurements from in situ space-based instruments and the high-energy data from the worldwide network of neutron monitors during ground level enhancements (GLEs). Reported results significantly improve the characterization of the most energetic SEP events. Measured spectra deviate from a simple power-law shape, exhibiting an exponential cutoff at high energies (several tens/hundreds MeV) that can be interpreted in terms of the limits of shock acceleration. No qualitative distinction between the spectra of GLE and non-GLE events was observed, suggesting that GLEs are not a separate class, but rather the most energetic subset of a continuous distribution of SEP events. We also took advantage of the superior energy resolution of the PAMELA instruments to calibrate the high-energy proton channels of the EPEAD and the HEPAD detectors on board GOES 13 and 15, improving the reliability of the spectroscopic observations of SEPs.

Speaker: Dr Alessandro Bruno (NASA/GSFC)

SOLAR ENERGETIC PARTICLE EVENTS OBSERVED BY THE PAMELA MISSION

10:40 → 11:10 Coffee - Thursday (AM)

11:10 → 12:00 Solar Energetic Particle Environment Modelling: 2

11:10 Magnetic Shielding Model (MSM) – A Parameterised Geomagnetic Shielding Calculation Tool

As part of the ESA ESHIEM project we developed the Magnetic Shielding Model (MSM) - a parmeterised model for calculating the transmission/penetration of charged particles into the Earth's magnetosphere A set of pre-calculated rigidity cutoff maps have been created using the PLANETOCOSMICS code and the rigidity cutoff for a given location and date within the magnetosphere can be quickly obtained by interpolation. In this talk we will report on the strategy of the map production, the interploation algorithm, and the validation effort; also we will discuss the limitations and the errors/uncertainties of the model.

Speaker: Dr Fan Lei

MSM Sykia WS2019.pdf

11:30 Discussion

Jiggens/SAPPHIRE:

SAPPHIRE is a model of solar energetic particle event fluence and peak flux. It generates these from virtual events, each with an event peak flux and event fluence and wait time (quiet time between events).

 

It covers confidence levels from 50-99.9%, missions from 3 months to 55 years, and worst week to worst 5 minutes. 5-300 MeV/nuc for H+, He++, 0.1-1000 MeV/nuc for Z up to 92. Also produces 1-in-n year fluences/peak fluxes, at requested confidence levels and mission durations. Helium model is separate from protons, and then heavier ions are done via abundance ratio.

P. Jiggens et al. JSWSC, 8(A31), doi: 10.1051/swsc/2018010, 2018. P. Jiggens et al. IEEE Trans. Nuc. Sci., 65(2), doi: 10.1109/TNS.2017.2786581, 2018. See https://spitfire.estec.esa.int/trac/SAPPHIRE/

Often lower than JPL and ESP, due to data treatment, allowing use of “more sensible” (i.e., higher) confidence levels.

Available in SPENVIS now and OMERE later in 2019.

Limitations:

• Does not produce virtual time series for detailed scenario analysis
• Uses average heavy ion abundances (varies within and between events)
• RDS v2 energies may change (highest energies only)

Going forward:

• Growing uptake
• Add higher energies for human spaceflight
• Address lower energy peak (<1 MeV)
• Merge with VESPER (virtual time series)
• Away from 1 AU

Questions:

• How do spectra extend to 1 GeV? Extrapolate using a Band fit, checked against neutron monitor data.
• Is the Poisson model of event rate valid? It’s an approximation that seems to be working, but there are some questions that remain, especially on short and long timescales.

Aminalragia-Giamini/VESPER:

VESPER is a probabilistic model that produces virtual time series of solar proton differential fluxes. It must account for wait time, duration, peak flux, fluence, and spectral coherence. Adapted the SAPPHIRE virtual time lines to generate durations and wait times. Model is heavily empirical.

Core of the model is the LF₂ variable, which is the integral of log(E²flux)dlog(E). Sum of LF2 over the duration of events is strongly correlated with the duration of events. Generate random cases of SLF2 given event duration. Scale real events using SLF2 – stretch in time and scale in flux.

Generated many virtual events with VESPER to compare to SEPEM for self consistency. Agreement is good, with only a few offsets.

VESPER is closer to SAPPHIRE than it is to ESP or JPL model, but there are some pending differences even between VESPER and SAPPHIRE yet to be understood.

VESPER has been coupled to MSM (Magnetospheric Shielding Model) to account for dynamic variation of solar particle access to satellite orbit over the course of events. Example shown for GTO-like orbit, with expected suppression of lower energies, and bigger effect for fluences than for peak fluxes.

Caveats/future work:

• Investigation filling/sampling of duration-SLF2 space.
• Sensitivity to event list
• Peak-flux to fluence relationship could be exploited
• Merging with SAPPHIRE

Questions:

• In comparison charts, how was JPL peak flux extracted (JPL does not do this natively)? What’s shown is the JPL fitting methodology applied to peak fluxes rather than fluences. It is not peak fluxes from the JPL model itself.
• When will heavy ions be added? Plan to start He in year 2 of ecIRENE, and rest of heavy ions in following year.

Aran/Time Series SEP:

(via Skype)

Concerned with SEP evolution away from 1 AU. Simple 1/R² assumption may overestimate the SEP fluence. Also does not account for in situ acceleration, e.g., by interplanetary shocks.

Physics-based models (most) can only model individual events, not overlapping series of events. Also, models often don’t model particle intensity after shock crossing. So, we have to split the observed events. What appears to be 1 or 2 events at Earth, may come from 4 different sources at the Sun. The higher energies are often important for revealing this multi-source structure. Dividing the events allows us to more appropriately address radial evolution through the heliosphere.

Generating a virtual event by rescaling an original event composed of multiple sources could cause problems. We may need to break up the events before doing the rescaling. We may also need to remove the backgrounds from the highest energy channels before creating virtual events.

Questions: None.

Bruno/PAMELA SEP:

Nominally two classes of energetic (>100 MeV, GLE) events. Impulsive (flares) and gradual (CMEs). Reality is probably a mixture.

PAMELA adds higher energies, plus pitch angle and species resolution.

Fit the event fluence with a  power law and a broken power-law: A (E/E_s)^gexp(-E/E₀) and simple power law. Broken power law fits better from 80-1000 MeV (26 examples shown). True of GLE and non-GLE events. Consistent with DSA theory. (DSA: Diffusive shock acceleration). Roll-over energy is correlated with event fluence, and starting frequency of Type II Radio Bursts & lower shock formation heights.

2012/0127 event spectral shape shows a break around 10 MeV as well as the broken power law at higher energy.

Well connected events tend to have higher fluence. Poorly connected high fluence events have to be long duration (>6 days). Well connected events have sharp increase and quick decay, whereas poorly-connected events have slower buildup, broader peak, and gradual decay.

GLE vs sub-GLE (sub-GLE seen only by South Pole neutron monitor): no difference in spectral shape.

Pitch angles: low energy population < 1 GV rigidity locally mirroring (scattered), and a high energy distribution > 1.5 GV beaming along field line.

Applied Sandberg calibration method to GOES HEPAD channel energies.

 

Questions:

• Is there a correlation between the broken power law fit parameters? Yes, the power-law spectral index is positively correlated with the roll-over energy (there is a backup slide showing this)
• Most neutron monitor fits are done in rigidity, not energy (as done here)? A power-law extending to infinity is unphysical, and the exponential cutoff (broken power-law) is more realistic.
• Are you suggesting the NM response function shouldn’t use the power-law, but use broken power-law (cutoff power-law)? Yes.
• Is PAMELA in LEO? Yes.
• Observed spectrum is corrected for geomagnetic cutoff? Yes, by only using observations outside rigidity cutoff.
• PAMELA cannot observe event continuously. How is this accounted for? (See “Data analysis” slide). Use a rigidity-dependent duty cycle, and interpolate over times when cannot see event, plus supplement with calibrated GOES data.

Lei/MSM:

MSM is the Magnetospheric Shielding Model, a tool for computing geomagnetic shielding cutoffs and Earth shadowing. Uses Geant4-based MAGNETOCOSMICS/PLANETOCOSMICS particle tracing code. Based on extended T89: TS89, Boberg’s 1995 extension, plus IGRF 2010 (1955 to 2015). Every 5 years, 5x5 lat/lon grid, at 450 km, every 3 hrs in UT, all values of Kp 0 to 9. Each map provides V(k), Stormer constant.

 

Average transmission function computed from vertical cutoff and Earth shadowing effect for each rigidity.

Caveats: not good for very disturbed conditions (T89). Day of year (season) not included explicitly, but is included via L interpolation.

Outlook:

• Update w/ latest IGRF
• Finer grid
• Improve map statistics
• Re-implement interpolation algorithms

Questions:

• We know T89 is not the greatest. Maybe do some case comparisons against more recent Tsyganenko models. There are some efforts, but difficult to engage collaborators because it’s not seen as interesting enough.
• It would be nice to have updated Kp-based external field model that’s better than T89. Error analysis so far is just comparing map resolution, not comparing to particle observation.
• We need to validate these cutoffs against in situ particle observations: Van Allen, PAMELA, PROBA-V/EPT (all have narrow field of view, narrow energy channels)

Discussion:

What is the release status of PAMELA data? (A. Bruno not in room to answer.)

A real-time monitor of cutoffs (probably based on LEO data) is needed. A proposal is in to NASA to do so, funding decision not made yet. ESA SSA program may be interested in such a project of its own.

How hard is it to make use of MSM? Right now, it’s a little convoluted, at least in ESPREM.

There is a need to update the CREME96 peaks & worst cases & GCRs.

SEPEM has a radial scaling system that’s roughly 1/R for fluence and closer to 1/R² for peak flux.

Proposing 50% worst case spectrum in a month, 95% worst case spectrum in a month, 95% worst case spectrum over mission. Big question is what time average to use? Also, behind how much shielding? This is a big challenge: there is no good single answer. We know the current approach of using a seemingly arbitrary number of worst days or worst weeks, or scale factors doesn’t work. But, we’re having a hard time defining what should be provided in a specification document, short of going back to the models and doing an onerous calculation with the full time series model.

An education note: many engineers mistakenly think that the solar particles are unaffected by shielding, but that’s only sorta true of GCR.

12:00 → 13:00 Modelling of the Radiation Belts and Plasma near Earth: 1

12:00 Simulating nearly 3 solar cycles in the electron radiation belts

Physics-based models of the radiation belts can provide time-dependent simulations of the high-energy electron flux, taking into account processes such as radial transport, wave-particle interactions, collisions with the atmosphere and losses to the magnetopause. To successfully reproduce observations, the simulations require appropriate boundary conditions and accurate descriptions of each of the processes included in the model. Typically these models are used to simulate specific events or longer periods of up to about year. Here we present a simulation of the high-energy (>100 keV) electron flux in the region between the outer edge of the inner belt and GEO for nearly 3 solar-cycles, made using the British Antarctic Survey Radiation Belt Model (BAS-RBM).
We describe a method that converts the >2 MeV flux measured by GOES at GEO into a differential flux spectrum to provide an outer boundary condition for the simulation. The simulation is validated using independent measurements made by the Galileo In-Orbit Validation Element-B spacecraft; correlation coefficients are in the range 0.72 to 0.88, and skill scores are between 0.6 and 0.8 for a range of L∗ and energies. The results provide a ‘climatology’ of the radiation belts; consistent features are present during different parts of the solar cycle and the average and peak fluxes also vary with the phase of the solar cycle. The worst case spectrum overlaps that derived independently for the limiting extreme event. A comparison between the simulation and the IRENE model identifies the locations and times where the two models differ significantly.

Speaker: Sarah Glauert (British Antarctic Survey)

SarahGlauert_IRENE_2019.pptx

12:20 Long term reanalysis of the radiation belt and ring current electrons

Data assimilation is a term used to describe various algorithms that help reconstruct the global state of evolution of the system from observations contaminated by noise. The most commo technique for the sequential data assimilation is called Kalman fileter ( Kalman 1960) produces sequential updates for the model forecasts using data. In this process the predictions of the physics based model are blended with observations from different sources and with different observational errors. This technique allows us to reconstract the previous state of the system, current state of the system, and also make very accurate predictions into the future as we can reconstruct the initial condition for the prediction. In this study we present reconstruction of the 4 years of radiation belts using the Versatile Electron Radiation Belt (VERB) code and Kalman Filtering. We also show a recent examples of the reanalysis of ring current electrons and discuss future applications this technique.

Speaker: Prof. Yuri Shprits (GFZ/UCLA)

12:40 Data assimilation technique applied to radiation belts and re-analysis data base

Ensemble Kalman filter based on the Salammbô code has been developed for years at ONERA. Model and data uncertainties are introduced in the filtering method so that uncertainties on the restitution are also available.

Re-analysis data based have been produced from the data assimilation tool and from the Salammbô code. Results will be presented and their uses in specification model development will be shown.

Speaker: Angélica SICARD-PIET (ONERA)

Assimilation_ONERA.pptx

13:00 → 14:15 Lunch - Thursday

14:15 → 15:50 Modelling of the Radiation Belts and Plasma near Earth: 2

14:15 Solar Cycle Variations of Low Altitude Protons

Solar cycle variations of low altitude protons are implicitly contained in the IRENE flux maps. However, IRENE users have requested an explicit solar cycle variation. Inclusion of such a model will require modifications to the IRENE data processing, flux maps, and software. We have developed simple models of the solar cycle variation based on the Selesnick Inner Zone Proton model (SIZM) and on data from the POES SEM-2 particle detectors. We discuss the ability of the models to predict the variations, as well as implications for the IRENE data base and software.

Speaker: Mr Stuart Huston (Confluence Analytics, Inc.)

Solar Cycle Variation Huston Greece 2019 final.pdf

14:35 A New Proton Low Altitude Radiation Belt (LARB) Model

Under the ESA project Radiation Environment at Extremely Low Latitude and Altitude (RENELLA, ESA Contract No 4000118058/16/NL/LF/hh), a new trapped model has been built for the low altitude region (<1,000 km).

The model flux maps are based on data from the S3-3/PT, AZUR/EI-88, CRRES/PROTEL, SAMPEX/PET and RBSP/REPT/RPS datasets. In addition, PROBA1/SREM data are used to validate the flux maps and routines to derive omnidirectional fluxes. All data were ingested in a local ODI (Open Data interface) instance, which greatly simplified subsequent data processing.

The data were binned in a set of maps using the Kaufmann $K$ and atmospheric density at the lowest mirror point as coordinate axis (one map per energy channel). Magnetic coordinate grids where pre-calculated for every year between 1960 and 2020, from which quadratic fits were derived for the minimum drift shell altitude as a function of $L$ and $I$. The MDAC atmosphere model is used to calculate density at the lowest mirror point, as a function of $F_{10.7}$ (90 and 7 day averages).

A first set of flux maps has been generated to verify the processing and modelling software, to perform a first order validation, and to start the implementation of the final model into the VALIRENE toolkit, SPENVIS and IRBEM.

Speaker: Dr Daniel Heynderickx

Sykia_LARB_2019.pptx

14:55 Detailed Validation of the IRENE Models and Assessment of Their Impact for Spacecraft Environment Predictions

The ESA VALIRENE Project is evaluating the performance of the IRENE models (v1.50.001) against proton and electron data from a number of different instruments, including those flown on INTEGRAL, PROBA-1, CRRES, XMM, and RBSP-A. To support this, an extensive reanalysis of the original data from these instruments has been undertaken to ensure well-calibrated, clean data are used for the comparisons. The validation of the IRENE as well as the AP8 and AE8 models against these datasets has focused primarily on the long-term mean environment for the spacecraft orbits, and long-term statistical variation of the environment as functions of McIlwain L and energy.
Comparisons have also been performed of the mean particle spectra and standard radiation effects quantities for standard spacecraft orbits, to explore the differences with using IRENE compared with more conventional models recommended by the ECSS-E-ST-10-04 space environment standard.
This paper will briefly summarise the data calibration and selection processes before presenting the model versus instrument-data and inter-model comparisons. An assessment of the relative performance of IRENE will be presented, its advantages and deficiencies, and the expected impact from adopting this model for spacecraft environment predictions. The results of the analysis includes recommendations for future IRENE model improvements, especially concerning the mean and long-term statistical variability of the electron environment.

Speaker: Dr Pete Truscott

15:15 AE9/AP9-IRENE Plasma Model: Future Development Plans and Needs

First released in 2012 and most recently updated in Version 1.55, the AE9/AP9-IRENE (International Radiation Environment Near Earth) model suite includes a standard plasma model (SPM), which extends the environmental specification from the traditional radiation energies of AE8/AP8 down to 1 keV for protons and electrons, while also adding helium and oxygen plasmas. As the IRENE suite evolves into version 2.0, the SPM will become more tightly integrated with the radiation models. This will necessitate addition of Monte Carlo capabilities and extension of the spatial domain to include the inner zone. Further, unlike the radiation belts, the plasmas have significant local time structure, and the current SPM does not represent that. Addressing all of these issues will require additional data sets and information that can best be provided by global plasma simulation models. In this talk, we will enumerate the planned data sets, and then identify the additional data and modeling needed to accomplish these upgrades.

Speakers: Dr Paul O'Brien (Aerospace Corporation), Dr Tim Guild, Dr William Johnston (AFRL), Mr Stuart Huston, Dr Y.-J. Su, Dr C. J. Roth, Dr Richard Quinn, Dr J. charron

201905_GREECE_SPM_final.pdf

15:30 AE9/AP9-IRENE Radiation Environment Model: Future Development Plans and Needs

First released in 2012 and most recently updated in Version 1.55, the AE9/AP9-IRENE (International Radiation Environment Near Earth) model suite provides the satellite design community with climatological specification of the near-Earth particle radiation environment for design and mission planning. The model is maintained with periodic releases improving both specification (via new or improved data sets) and capabilities (via new component models). Here we review planned future IRENE development and the desired contributions from the scientific/engineering community needed to enhance this development.

The forthcoming IRENE Version 2.0 will entail an architecture overhaul to modularize the component models. Existing component models may then support additional dimensions, e.g., local time dependence for plasma. As a result, component models will be independent in their coordinate systems, enabling use of the most appropriate system for a given hazard. The suite’s core functions will include seamless stitching of model results in space and energy as necessary for the user’s request. New modules will be supported with the first of these being one for untrapped solar protons and another with a historical sample solar cycle. Core functions also include appropriate merging of statistical results from component models to ensure accuracy of confidence limits for the hazard of interest. This maximizes utility of the kernels-based effects capability which in V2.0 will support user-defined kernels in addition to standard kernels for various effects hazards (e.g., dose, single event effects, and internal charging).

These intended upgrades depend on contributions from the community. We are working to include additional domestic and international data sets to address known areas of need in spatial and energy coverage. The sample solar cycle will be a fly-through option using a historical reanalysis, for which we have several candidates, enabling users to evaluate realistic dynamic hazards on short timescales not captured in the current model suite. Other areas where community models can support improvements are adding solar cycle variation in low altitude protons, adding correlations over particle species, and improving accuracy of altitude and pitch angle gradients where data coverage is sparse. Potential new modules in later versions include ones for auroral particles and plasma sheet particles. We will provide more details of our “wish list” for models and data sets needed for planned model improvements.

Speaker: Dr Paul O'Brien (Aerospace Corporation)

201905_GREECE_IRENE_final.pdf

15:50 → 16:20 Coffee - Thursday (PM)

16:20 → 17:45 Modelling of the Radiation Belts and Plasma near Earth: 3

16:20 Lessons from RBSP/HOPE data Investigations

Surface charging of spacecraft in geostationary orbit is a familiar problem that continues to cause failures and operational difficulties to geostationary spacecraft. Spacecraft in other orbits within the magnetosphere beyond the plasmasphere, e.g. in global navigation orbits or in transit to geostationary orbit via electric orbit raising, experience a plasma environment qualitatively similar to that at GEO and charging is observed in this region. However, the plasma characteristics are not identical to GEO. Current standards specify only a GEO worst case. A more comprehensive plasma model to assess high charging levels is needed.
RBSP’s near equatorial, GTO-like orbit gives the two spacecraft wide coverage of the magnetosphere below geostationary orbit. Using HOPE data, we looked at charging events in the RBSP and examined the characteristics of the dataset. We consider what is needed for an empirical model of the charging environment and how the RBSP data may be used as input to such modelling.

Speaker: David Rodgers (ESA)

IRENE Hope charging environment.pptx

16:40 Data assimilation of electron radiation belts

The dynamical evolution of the outer belts should be a delicate balance among several processes. In order to discriminate what physical processes are dominant for the large flux enhancement of the outer belt electrons, we have developed the data assimilation code on the outer belt electrons. In our data assimilation, the particle filter and the particle smoother are used for the assimilation, which are effective for the non-linear/non-Gauss distribution problem. We include the radial diffusion coefficient and the internal source model as the state vector and estimate the dynamical variations of these parameters. The results indicate that only the radial diffusion process is not always enough to explain the observed flux enhancement and the internal source process should be necessary. The assimilation result suggests that the internal source process tend to take place around the storm recovery phase, which is consistent with the observations.

Speaker: Prof. Yoshizumi Miyoshi (ISEE, Nagoya University)

IRNE_Miyoshi.pdf

17:00 Discussion

Radiation Belt and Plasma near-earth

 

BAS 30-year simulation - Sarah

[Use results slide image 1986-2016]

Motivation for accommodating needs of MEO environment including GPS/Galileo + O3B and EPOR

Satellites should last ~20 years

BAS model including transport and waves

Boundary conditions: min/max pitch angle (gradient set to 0); Emax flux set to 0 [+kp??]

Outer L* boundary based on GOES >2 MeV e- flux

Model needs drift-average differential flux spectrum with Fixed L*

Spectrum shape approximated from GOES-MAGED

Kappa distribution fitted to PSD

Very good agreement with AE9 at GEO for 100cm-2sr-1s-1keV-1 at GEO

Short-term variability shows storms and electron desert

Impenetrable barrier from Baker is not valid at all times

When slot region is enhanced it can take weeks to return to normal levels (even if recently it has been benign)

Limiting from from Meredith is very close to the BAS model output (even better if we just look at IREM)

Validation done on SREM count rates from Giove-B. [would be great to re-visit this for Galileo/EMU]

Skill scores in the range of 0.6 to 0.8

 

Output covers L*/pitch-angle/energy

 

Making use of simulation:

POB

Long-term spatial-temporal correlations for outer zone for range of timescales up to decades.

Filling the energy range where instruments lacks channels and using PADs

Using model to get back to the uni-directional fluxes

L*=2 limits the applications of the model for EPOR or LEO satellites (600 - 1000 km) - being looked at in Rad-Sat project

Incorporate a ring current model

 

PAD included

75GB output file size in raw form at present

 

IS

Correlations with magnetospheric indices as well as data

 

Long-term reanalysis (Yuri)

[3-d model slide with data with single boundary condition]

Need to separate data assimilation and modelling.

Extent of need for actual modelling is limited where we have good data and can do assimilation instead.

Data assimilation allows us to match data and model results and produce a Global flux map output.

Data -> model for next time step -> Kalman filter to incorporate more data -> step forward

Peaks in PSD are better generated with data assimilation

Assimilation: Can combine range of data sets and weight based on data quality; Good for post-event reconstructions; Good for initial conditions for forecasting.

GEO/GPS/LANL/POLAR data used to blend model and data and to derive 

Have 1-d and 3-d (VERB) model used with single boundary condition and then extended to use VAP and GOES (fluxes and PSD)

VAP will stop in one year and is nominally not operational. POES can help create a good reconstruction of the environment.

Convection model of ring current electrons based on different model due to different physical equations - VAP data useful for this reconstruction.

Forecast predictions can be quite accurate for ~2 days due to time it takes to extend.

 

What is the longest simulation you presently have? Oct 2012 - Oct 2016 10s keV up to >3 MeV

Ring current model takes more time with TBytes data output

NASA interested to get CCMC to run data assimilative models for climatology for re-analysis

SSA is getting aware. They should want to put nowcast and forecasts into a longer-term context.

VERB predictions is running operationally

 

ONERA data assimilation (Angelica)

[slide 7-9]

Funding by CNES and FP7 (MAARBLE)

Data assimilation using Salammbo combined with data. Running 200 runs of Salammbo in parallel and then selecting the output(s) to propagate on the basis of data check (counts or fluxes)

Set of boundary conditions to run ensemble mode based on distribution of fluxes based on Kp along with energy-energy correlations

Bw median and stdev considered.

Radial diffusions also sampled randomly with correlations considered.

Re-analysis with ensembled Kalman filter; e- 03  - 5 MeV; mean and std of PSD; 10-min resolution; 6 weeks output - up to 15 years for electrons and almost 30 years for protons.

Basis for the OZONE model and used in GREEN-e (4<L<8) and GREEN-p (1<L<6)

 

Good to use actual response and counts for the assimilation process. Need: to have the response functions and count rates!

How do you use the count-rate check when the have a range of spectra coming from the model?

Drop-out in POES trapped protons get captured by the SALAMMBO model? Seems to over-estimate fluxes.

 

What's the relation between static (data-driven) models in GREEN? AS: not decided but thinks the best will be to use the data assimilation output as the basis and check against existing models.

 

IRENE Cycle Variation (Stu)

[example POES inverted fluxes]

User request for low-altitude protons - controlled by atmosphere as much/more than magnetic field

Inside IRENE need to be able to map to some kind of reference state

How will it be used? Factor 10 differences are possible but those are in regions of low flux

How can we forecast solar cycle to use this analysis? Cycle appears at different times (lag) for different energies...

Requirement to cover: 0.1 - 2000 MeV; 0<K^0.5<3; 0 < hmin < 1000

Correlation of flux related to F10.7 (with phasing lag) - using POES/Selesnick Inner Zone Proton Model (SIZM) to derive parameters (lag, h_min and flux scaling)

SAMPEX data not used at present but there are plans to reprocess that and then make use of it.

DH: Why K^0.5 and not K? SH: Seems better results away from equatorial region.

DH: Why are you using hmin? POB: Basically we found it was a better measure of the low altitude environment.

RH: factor 10 variation in POES data inverted, do you need anything beyond the worst case? SH: Previously we were just using solar min design, user case it not clear.

 

LARB (Daniel)

[model maps, e.g.slide 17]

Reconstruct PSB97 for quick revision of mission rad. env. (previously XIPE, now THESEUS)

Then establish the new LARB model.

<1000 km & 0.1 - 1000 MeV p+

Fluxes range from 10^6 down to 10^-3

10 deg pitch angle bins on REPT not easily mapped to equatorial pitch angle - N.B. equatorial pitch angle not used for the model

RPS has

L, a_eq breaks down at these low altitudes so h_min used along with density parameter, n, as a proxy of L* 

h_min is found tracing the drift shell but claculation is heavy so parabolic fits are using

Plan to use REPT to cover part of K v n map that SAMPEX doesn't

Geographical maps starting to come together - some more cleaning to be done

 

SH: using rho instead of h_min doesn't seem to improve performance

DH: hoping to capture the density in the same fit

RH: anything else matters apart from density?

DH: Well, there are injections but it's not clear how these should be incorporated

 

VALIRENE Toolkit

[slide 5 or 8]

Validation toolkit for the Ap9/AE9/SPM models against in-situ data sets and comparisons to other ECSS-recommended models also performed

Outputs also given for effects quantities.

Data used includes SAMPEX, EPT, PROBA-1/SREM, TSX-5/CEASE and AZUR + MERLIN, GPS, etc....

IRENE outputs of perturbed mean account for the uncertainties ain flux maps whilst m-c results are needed to capture space weather impacts

INTEGRAL p+ results shows that medium L ranges at lower energies AP8 appears to do better but all high energies AP9 appears to be better

RPS p+ data is almost always better matched to AP9 than AP8

INTEGRAL e- shows that for the most part one of AE8 max/min are better than AE9

However, for CRRES/MEA e- AE9 appears to be equally out-performing of AE8

AE9 doesn't appear to capture the variabilty even in M-C mode

AE9 appears to fall between MEO upper and MEO mean

Low-altitude high inclination orbits are not well-captured by IRENE

At GEO AE9 and AE8 are higher than IGE-POLE

EPOR for <1 year should use M-C mode of operation

 

YS: How do you know that the data sets are valid 

PT: We also passed the fluxes from the model through the responses to compare counts which seems to show similar results.

 

YS: 1990-1991 CRRES/MEA should be higher than the model

PT: The comparisons don't bear this out

 

IJ: Your thinking is that if you use IRENE be cautious?

PT: There are cases fir the electrons where even 95% doesn't appear to span up to some of the data set yearly variables.

POB: This is really due to the nature of IRENE as a consensus model and data sets (especially e-) have likely much higher intrinsic errors than data owners claim

 

AE9/AP9-IRENE (Paul)

[image?]

V1.55 to US gvt contractors in 04/2019

v2.0 planned to include solar protons and sample solar cycle

Need: long-term (> cycle) assimilation (or just physics) run output (10 eV - 10 MeV e- and 10-eV - 1 GeV p+, 10 eV - 200 keV He+, O+

Like to check also the low altitude electrons (e.g. using DEMETER data)

Inside model all distributions are Weibull or lognormal. In AE9 this creates discontinuities.

Could use TREPEM-style approach but hard to capture the errors when you don't have a distribution fit

Effects kernels in V1.55 will replace SHIELDOSE2 and extend to charging

Need: thin shielding dose tools, plasma effects and ion effects

POB: for development the python version will be shared within collaboration

RH: why is the low altitude stuff so hard? It's well-understood.

POB: We need (physical) models we can use that get the numbers right

 

YS: What is plasma in this context?

POB: 40 keV cut-off between plasma and radiation

 

YS: What's the use case?

POB: Material degradation primarily

YS: What about surface charging?

POB: In the design scenario you probably take more of a worst-case scenario

 

SPM-IRENE (Paul)

Tim Guild is the main author.

Want to include MLT variation in the plasma model - nothing in there presently

Grid parameters are Energy, Lm and equatorial pitch angle

Coverage issues are being addressed including THEMIS from v1.2

Limit of 1 keV due to high scatter in conjunctions preventing any kind of cross-calibration between plasma analysers

Templates taken from data sets supplemented by models

Issues: only 1 data set including composition, no mean local time variation

Plan to include HOPE in some way even though it cannot operate that well in the inner zone due to interference

Would like ring current simulators as well.

 

YS: Can HOPE not become a gold standard?

POB: Should be able to be

 

JAS: Why does you use the Cluster CIAS data which has time-of-flight and composition?

POB: Initially it wasn't in an interesting orbit, we might have to re-look at it.

Yoshi: Has up to 200 keV data which could be included inside the model (LEPI and MEPI on Arase).

 

HOPE Plasma data analysis (Dave)

[slide 8,Plasma interactions drive high-level charging

NASA and ECSS have worst case for GEO but other orbits aren't well specified for this effect

HOPE is a top-hat ESA with time-of-flight allowing energy + mass to be determined

Data has been ingested into ODI (25 eV - 51.8 keV)

Charging events result in acceleration of protons (so we don't see the lower energies) - Can check HOPE output against the E-field and waves instruments (but that is limited to 200 V whereas HOPE measures events up to 1000 V)

As is well known the events all occur in the midnight-dawn region of the orbit

Strangely events were mainly seen in 2012 - 2013 (perhaps resulting from a change in material properties)

Rare temperature enhancements show bit enhancements which are most pronounced at L=6 - 6.5

Mean data appears to show peak at L = 3 (would need to be further investigated)

Need electron and ion Maxweillian temperature and density and to see if the data is well fit by these during charging events (data may need to be corrected)

Temperature alone doesn't seem sufficient (maybe a flux ratio at different energies)

 

POB: Can we use 10 keV e- flux instead of temperature

DR: There are many people using different proxies which is an issue.

 

POB: How can we filter events to derive the worst-case for spacecraft specification

DR: Indeed 

 

Arase (Yoshi)

1-d Fokker-Planck solver with assimilation using Particle-filter

Prediction from distributions of state (vectors) are then compared to data to give a weighting for the likelihood and then resampling of the data based on this before next set of state vectors are given.

Radial diffusion coeff, lifetime and internal source parameters are output state.

400 - 800 keV electrons

Inclusion of internal source process improved results based on MAPE proxy for time series performance.

Arase data XEP (similar to REPT) to be extended into 2022/2023

 

RH: What range of energies does the source need to cover?

YM: 300-400 keV

 

Discussion

POB: We talked about gap filling for environments but templates in IRENE has resulted in kinks in the data. Can use data assimilation in this but would require running the data assimilation inside the model

YS: Can be done but we should add derived dose which is measured(?) and the number of steps that are run is important for smoothing

POB: Should use the BAS model but we might like something which has more of a data assimilative aspect than just GEO boundary conditions.

YS: Need to work out how to use LEO data

POB: we will need to translate the outputs into the IRENE coordinates system from PSD.

We would need to investigate funding process for comparing and integrating data assimilative model outputs.

 

PJ: Can we really include modes for cycle phases due to how poor cycle predictions tend to be.

YS: For cubesats where the production time is very short one it could be reasonable. They would like to understand to fix launch dates

POB: Tends to be unlikely that someone builds a line of satellites on the basis of being able to launch at only one phase of the cycle.

PJ: If you want to use a cycle phase then it should be used to build a historic picture to capture variability and confidence

RE: We need to define what we want to use for worst cases for spacecraft designers to make use of models.

PJ: How can we work on kinks introduced with low altitude models as opposed to 

SH: Doing the templates is the present effort to line these things up.

POB: Using physics-based models at LEO with protons

AS: LEO included as well as we can right now.

POB: OPAL is broadly based on data rather than physics-based modelling.

Inner zone p+ needs to be developed including CRAND and to go down to lower energies (100 keV) whereas now there is an issue below 20 MeV

DH: Need to get people to clean data and introduce processes so we don't have to keep re-processing it.

DH: We are also duplicating effort in cleaning these things up.

PJ: There are issues of trust but no longer issues to release the factors produced under our contract because it's now approved for o/s

POB: Probable in AFRL that this is as much a process issue than something intractable 

18:45 → 23:00 Conference: Excursion & Dinner

Friday 31 May

09:30 → 11:05 Effects Tools and End User Perspectives: 1

Talk by SC (ESA)

- Concerns about model and data interpretability

- Services (require IT experts)

- Complex interfaces between ESA models/services

- Need to standardize models; description, model outputs, data types

- Networks of models concept: model specification

- Networks of models -  General requirements

- Example: Easy, robust interoperability of SPENVIS, ESPREM, ODI

 

DHC: A lot of work presented involves metadata. Standardize metadata and proper use of them.

PoB: How do you tie this requirements to user needs? To achieve the standardization goal you need to demonstrate existing use cases/ user needs.

DHC: HAPI standards are under development

________________________________________________________________________________

Talk by Insoo Jun (JPL/NASA): Radiation Assessment for JPL Missions Models and Tools

- SAPPHIRE: to be considered for use in the futre

- Issues appear some cases with AP9/AE9. 

- GIRE4 with Juno data; noisy with background

- Dose-depth curve is convinient & fast but an estimation

- Transport Codes are needed which model actual particle interactions

- Shielding Design Lessons Learned: Multiple iterations, comprehensive physics package

- Presentation of charging tools (NUMIT for IC, NASCAP-2K for SC)

 

Yuri: Zoo of different talks/tools. Can we validate, cross-compare EU/ESA vs US/NASA tools?

JI:- Issues with IPR. We try to make open source. It is a case by case issue.

Yuri: Comparisons with DICTAT?

JI: Yes. Differences do exist.

Yuri: Write a paper on charging comparing charging tools?

JI: Nice idea

PJ: Do you use Jason radiation data?

JI: Yes, for comparisons with IRENE we have used Jason-2

PJ: Do you have resources?

JI: Yes.

_____________________________________________________________________

RH talk on  "Satellite Charging at Geostationary Orbit"

- Galaxy IV case

- Why did not all s/c suffer anomalies?

- Daily electron fluence as a key factor

- Resistivity (RC) defines the time constant - calculation results for RC may differ dramatically (non contact methods)

- Recurrent fast SW streams: max charge accumulation occur after peak daily flux & last for days

- Need to: update materials/Spenvis, incorporate effects of different time constants

 

[D. Rodgers]: Information on materials on SPENVIS do exist. Proper use by users required

[HE]:

[DR]: 

[JI]: Temperature effects are also important

[PoB]: Discharges occur many times/frequently per day. They do not lead necessarily/usually to damages/impacts. We miss something to understand what actually leads to anomalies when a discharge occurs. Different behavior from vehicle to vehicle. Scatha case.

[Simon]: Have you considered Temperature effects? No

_____________________________________________________________________

AL talk on  "Evaluation of Solar Cell Radiation Damage during Electric Orbit Raising"

-  2%-5% variability in doses depending on EOR apogee (two cases studied)

-  2%-5% variability in doses depending on quiet/active models

- Recommendations: a)

 

PoB: You build your study based on power loss. A different approach would be to ...

PJ: What is the actual width of cover glass? 

PJ: Future EOR will terminate on MEO? 

 

________________________________________________________

Talk by MD: The ESA SSA Space Weather Space Radiation Expert Service Centre

PoB: Requirements for Operational tools/services?

MD: Data stream requirements

Yuri S: Transition issues from ACE to DISCOVR.

IS: Is there consensus on the data type format and APIs between ESA/ESTEC and SSA program

________________________________________________________

Talk by AV: FASTRAD & OMERE

- Feedback from partners & from users.

- Involve industry from earlier stages in the model development

 

PoB: With AE9/AP9, we asked industry in advance. We developed model accordingly.

AV: It is important HOW to present results to the users

PoB: User interface can by provided by UI tools (e.g. SPENVIS, OMERE)

HE & PoB: There exist different user cases. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

09:30 Future harmonization and access to ESA environment and effects models.

SPENVIS is among several tools and services that will continue to be important components of the tools available to the space environment and effects community. The current state of these tools will be discussed along with planned future work to enable their continued use within future agency and industry activities.

Speaker: Simon Clucas (ESA)

irene-furture-harmonisation-sclucas.pdf

09:50 Tools used for space radiation design for JPL space missions

The Jet Propulsion Laboratory (JPL) is a NASA center who specializes in robotic explorations of the Solar System. Radiation design is a key consideration for all space missions at JPL. Here, by "radiation design", we means all design activities related to ensure for the safety and success of missions in the radiation environment expected during the missions. It typically involves radiation environment definition and specification, EEE parts selection, radiation analysis and testing,etc. All aspects of radiation effects should be considered for the successful radiation design. Typical radiation effects that should be considered are total ionizing dose (TID), displace damage dose (DDD), single event effect (SEE), surface and internal charging. Depending on mission target, certain types of radiation effects will be more important than other effects. For example, a mission to Jupiter where high energy electron environment is the dominating contributor for radiation effects, internal charging design could be more important than others.

To assess all these radiation effects, various tools are being used for different purposes during the life cycle of a mission. Those include environment models, radiation transport codes, or charging codes. In this talk, we will especially discuss tools being used at JPL for shielding design and charging risk assessment, namely, FASTRAD, NOVICE, MCNP, Geant4, ITS, and NASCAP-2K, and NUMIT. The focus will be to discuss how they are being used at different stages of the flight project cycle for what purposes.

Speaker: Insoo Jun (NASA/JPL)

JPL_Tools_Insoo_Jun.pptx

10:10 Satellite Charging at Geostationary Orbit

At geostationary orbit periods of elevated high energy electron flux can cause satellite charging leading to disruptions to satellite services and in exceptional cases satellite loss. Here we examine the time history of the electron flux at geostationary orbit using data from the GOES satellite. We consider the peak flux and 24 hour fluence and examine periods where satellites may be a risk. We adopt a model for satellite charging that takes into account the properties of difference dielectric materials. We demonstrate that the charging risk is far more complicated than simply looking at the electron flux and depends critically on the time history of the electron flux. We discuss what this means in terms of protecting satellites and the difficulty of calculating the risk for orbits where there are little data, such as medium Earth orbit.

Speaker: Richard Horne (British Antarctic Survey)

10:30 Evaluation of Solar Cell Radiation Damage during Electric Orbit Raising

Electric propulsion technology now enables satellite operators to achieve geostationary orbit without the use of chemical propellant via so-called electric orbit raising. This enables lower cost access to space by reducing wet mass, but necessitates a longer raising period, during which satellites pass through the hazardous radiation environment of the Van Allen belts.

Increased radiation exposure during electric orbit raising must be accounted for by mission planners through the use of radiation environment models such as NASA’s AE-9/AP-9. However, case studies such as the CRRES mission show that our predictive capability is limited by the drastic changes to the proton (inner) belt and slot region that can occur in a worst case scenario. Furthermore, the lack of consensus in industry as to which models provide suitable estimates raises the risk for shielding to be over or under-designed.

We show the accumulation of damage calculated by a range of models in terms of non-ionising dose for a variety of electric orbit raising scenarios that have been used to date, and discuss how varying key parameters affects the result. We use the reduction in solar cell performance as a measure of degradation, with the dominant contribution coming from 3 – 10MeV trapped protons.

In particular, we show that the trajectory, solar cell coverglass thickness and state of the proton belt can affect solar cell degradation accrued during electric orbit raising and before the beginning of service by up to ~10%. We conclude that more real-time information is required on the transient nature of the proton belt’s outer region to help assess radiation damage.

Speaker: Mr Alexander Lozinski (British Antarctic Survey)

IRENE_BritishAntarcticSurvey_EOR.pptx

11:05 → 11:35 Coffee - Friday (AM)

11:35 → 13:00 Effects Tools and End User Perspectives: 2

Talk by SC (ESA)

- Concerns about model and data interpretability

- Services (require IT experts)

- Complex interfaces between ESA models/services

- Need to standardize models; description, model outputs, data types

- Networks of models concept: model specification

- Networks of models -  General requirements

- Example: Easy, robust interoperability of SPENVIS, ESPREM, ODI

 

DHC: A lot of work presented involves metadata. Standardize metadata and proper use of them.

PoB: How do you tie this requirements to user needs? To achieve the standardization goal you need to demonstrate existing use cases/ user needs.

DHC: HAPI standards are under development

________________________________________________________________________________

Talk by Insoo Jun (JPL/NASA): Radiation Assessment for JPL Missions Models and Tools

- SAPPHIRE: to be considered for use in the futre

- Issues appear some cases with AP9/AE9. 

- GIRE4 with Juno data; noisy with background

- Dose-depth curve is convinient & fast but an estimation

- Transport Codes are needed which model actual particle interactions

- Shielding Design Lessons Learned: Multiple iterations, comprehensive physics package

- Presentation of charging tools (NUMIT for IC, NASCAP-2K for SC)

 

Yuri: Zoo of different talks/tools. Can we validate, cross-compare EU/ESA vs US/NASA tools?

JI:- Issues with IPR. We try to make open source. It is a case by case issue.

Yuri: Comparisons with DICTAT?

JI: Yes. Differences do exist.

Yuri: Write a paper on charging comparing charging tools?

JI: Nice idea

PJ: Do you use Jason radiation data?

JI: Yes, for comparisons with IRENE we have used Jason-2

PJ: Do you have resources?

JI: Yes.

_____________________________________________________________________

RH talk on  "Satellite Charging at Geostationary Orbit"

- Galaxy IV case

- Why did not all s/c suffer anomalies?

- Daily electron fluence as a key factor

- Resistivity (RC) defines the time constant - calculation results for RC may differ dramatically (non contact methods)

- Recurrent fast SW streams: max charge accumulation occur after peak daily flux & last for days

- Need to: update materials/Spenvis, incorporate effects of different time constants

 

[D. Rodgers]: Information on materials on SPENVIS do exist. Proper use by users required

[HE]:

[DR]: 

[JI]: Temperature effects are also important

[PoB]: Discharges occur many times/frequently per day. They do not lead necessarily/usually to damages/impacts. We miss something to understand what actually leads to anomalies when a discharge occurs. Different behavior from vehicle to vehicle. Scatha case.

[Simon]: Have you considered Temperature effects? No

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AL talk on  "Evaluation of Solar Cell Radiation Damage during Electric Orbit Raising"

-  2%-5% variability in doses depending on EOR apogee (two cases studied)

-  2%-5% variability in doses depending on quiet/active models

- Recommendations: a)

 

PoB: You build your study based on power loss. A different approach would be to ...

PJ: What is the actual width of cover glass? 

PJ: Future EOR will terminate on MEO? 

 

________________________________________________________

Talk by MD: The ESA SSA Space Weather Space Radiation Expert Service Centre

PoB: Requirements for Operational tools/services?

MD: Data stream requirements

Yuri S: Transition issues from ACE to DISCOVR.

IS: Is there consensus on the data type format and APIs between ESA/ESTEC and SSA program

________________________________________________________

Talk by AV: FASTRAD & OMERE

- Feedback from partners & from users.

- Involve industry from earlier stages in the model development

 

PoB: With AE9/AP9, we asked industry in advance. We developed model accordingly.

AV: It is important HOW to present results to the users

PoB: User interface can by provided by UI tools (e.g. SPENVIS, OMERE)

HE & PoB: There exist different user cases. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11:35 The ESA SSA Space Weather Space Radiation Expert Service Centre

In the frame of its Space Situational Awareness (SSA) programme, the European Space Agency (ESA) is establishing a Space Weather (SWE) Service Network. This network is organised in five Expert Service Centres (Solar Weather, Heliospheric Weather, Space Radiation, Ionospheric Weather, Geomagnetic Conditions) with online products and tools and is supported by the SSA Space Weather Coordination Centre (SSCC) that offers first line support to the end users. The domain of the Space Radiation Expert Service Centre (R-ESC) covers the monitoring, modelling and forecasting of space particle radiation and micron-size particulates, as well as all types of phenomena induced effects on technologies and biological systems concerning the near-Earth space environment. The mission of the R-ESC is to provide and develop functionalities, capabilities and expertise in its domain in order to provide services to end users. The R-ESC is currently a network of thirteen Expert Groups (8 product providers and 5 consultants), and is coordinated by the Royal Belgian Institute for Space Aeronomy. This presentation will focus on the R-ESC products related to the near Earth plasma environment, radiation belts, and solar energetic particles that have been integrated and developed. An overview of the activities providing valuable input for the further development of the R-ESC, like assessments of current capabilities, end-user feedback and maintaining service development roadmaps, will also be given. This work is being performed under the ESA SSA SWE program (contract No 4000113187/15/D/MRP).

Speaker: Mark Dierckxsens (Royal Belgian Institute for Space Aeronomy)

Dierckxsens_R-ESC.pptx

11:55 OMERE and FASTRAD©: working with the users

OMERE and FASTRAD© are being developed and distributed by TRAD for more than 15 years now. OMERE is a freeware that allows to define the radiation environment for a space mission, from particle fluxes to dose-depth curve (TID, TNID) and SEE rates. Concerning the Earth’s radiation belts, several engineering models are available, including the AE9/AP9 models. FASTRAD© is a 3D CAD tool for the radiation analysis (TID, TNID) at component and material level. Both Ray-Tracing and Monte Carlo (FMC, RMC) methods are available allowing to perform a precise analysis and, in combination with post-processing tools, optimise design to mitigate against radiation risk. OMERE and FASTRAD© have been developed in a compatible way: OMERE outputs can be directly used in FASTRAD© and vice-versa.
This presentation will focus on the lessons learned during all these years working with the users of both software. The process for integrating a new environment model in OMERE will be presented and the compatibility with the radiation analysis at FASTRAD© level will be discussed.

Speaker: Dr Athina Varotsou (TRAD)

12:15 Discussion

13:00 → 14:00 Conference: Workshop Wrap-Up and Close

13:00 Discussion