Speaker
Dr
Sarah Glauert
(British Antarctic Survey)
Description
The flux of relativistic electrons in the Earth's radiation belts is highly variable and can change by orders of magnitude on timescales of a few hours. Understanding the drivers for these changes is important as energetic electrons can damage satellites. Forecasting the high-energy electron flux in the radiation belts is a challenge that has been taken on by the FP7 project SPACECAST. The BAS radiation belt model, which is used in the SPACECAST project, solves a 3-D Fokker-Planck equation incorporating the effects of radial transport, wave-particle interactions and collisions to model the electron flux throughout the radiation belts. Wave-particle interactions are incorporated into the models as pitch-angle and energy diffusion coefficients. Here we present results from the BAS radiation belt model, using new pitch-angle and energy diffusion coefficients for whistler mode chorus waves produced by the SPACECAST and MAARBLE projects and new diffusion coefficients for plasmaspheric hiss and lightning-generated whistlers developed at BAS. We demonstrate that the model can reproduce the observed flux both during storms, where acceleration by chorus waves is important in the outer belt, and during quiet periods, where losses due to plasmaspheric hiss create the slot region. We also show that the wave-normal angle used to calculate the diffusion due to plasmaspheric hiss is crucial. Several wave-normal angle models for plasmaspheric hiss are considered; using a peak wave-normal angle that varies with latitude gives the best results. Finally, our results demonstrate that radiation belt dynamics are reproduced better when the AE index, rather than Kp, is used to drive the wave-particle interactions.
Primary author
Dr
Sarah Glauert
(British Antarctic Survey)
Co-authors
Dr
Nigel Meredith
(British Antarctic Survey)
Prof.
Richard Horne
(British Antarctic Survey)
Mr
Tobias Kersten
(British Antarctic Survey, Cambridge, UK)
