Speaker
Dr
Harri Laakso
(ESA)
Description
The inner magnetosphere contains two plasma regimes, the plasmasphere and radiation belts, that are coupled to each other. The plasmasphere can support various wave modes that can cause either energization of radiation belt particles or their loss. In particular hiss emission is believed to provide a major loss mechanism of energetic particles Using in-situ multi-point observations from the four Cluster satellites we investigate this region in the dusk sector where large-scale plasmaspheric plumes are regularly formed. The plumes can be observed in nearly all times, although their characteristics depend upon the level of geomagnetic activity. Within the plumes that are 1-2 L shell wide, the plasma drift velocity is 5-20 km/s westward/noonward. The plumes are observed to contain enhanced hiss emission for most of the time, and this hiss emission is observed to be generated at the equatorial region of the plumes and the hiss intensity is highly correlated with local plasma density. Within the plasmasphere the hiss is also observed but in this region the hiss is seen to propagate from the polar regions towards the equator. Again the hiss intensity is seen to be well correlated with local plasma density.
Primary author
Dr
Harri Laakso
(ESA)
