Abstract
We investigate the effects of intense chorus waves (wave power >10⁻⁴nT²) on relativistic electrons (E > 0.5 MeV) in the heart of the outer radiation belt (L* = 4–6) using superposed epoch analyses. 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 0–0.5 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.
Key Points:
• Intense chorus waves appear to be associated with the mitigation of main phase loss of outer radiation belt relativistic electrons
• Loss mitigation related to chorus waves appears to be most effective at L* = 4.5 in the energy range 1.1–2.6 MeV during storm main phase
• The amount of keV electrons appears to determine the consequences of the intense chorus waves on the relativistic electron population