Intense chorus waves mitigate the loss of outer radiation belt
relativistic electrons during storm main phase
Abstract
We investigate the effects of intense chorus waves (wave power
> 10-4 nT2) on relativistic electrons (E > 0.5
MeV) in the heart of the outer radiation belt (L* = 4 - 6) using
superposed epoch approach. Combining electron flux and electromagnetic
wave measurements from 70 geomagnetic storms during the Van Allen Probes
mission, we show the relationship between integrated chorus wave power
(0.1 - 0.8 equatorial electron gyrofrequency) and changes in
relativistic electron flux on two hour timescales. During the
loss-dominated storm main phase (Superposed Epoch -0.5 to 0 days),
intense chorus waves mitigate the net loss of relativistic electrons.
Conversely, in the early recovery phase (Superposed epoch 0 to 0.5
days), flux increases across a range of relativistic energies regardless
of chorus wave power. The amount of electron flux at keV energies
appears to have an influence on the consequences of chorus wave activity
during geomagnetic storms.