Nonlinear interaction of energetic electrons with large amplitude chorus

Abstract

[1] The effect of large amplitude chorus on energetic, radiation-belt electrons is evaluated using a general, relativistic, oblique, test-particle code. Three specific cases are examined: (A) Low-amplitude waves interacting at lowlatitudes exhibit the expected, linear scattering which leads to large-scale diffusive behavior. (B) Large-amplitude waves interacting at low-latitudes result in monotonic decreases in pitch-angle and energy due to a resonance dislocation effect, leading to large-scale de-energization and particle loss. (C) Large-amplitude waves interacting obliquely at high latitudes result in a combination of the above behaviors, as well as nonlinear phase-trapping which leads to rapid, dramatic increases in both energy and pitch-angle of a small portion of the test-particles. These results suggest that the intensity of individual, discrete wave elements is critical for quantifying the large-scale dynamics of the radiationbelts.

Effects of amplitude modulation on nonlinear interactions between electrons and chorus waves

“…These single-wave nonlinear theories predict nonlinear phase bunching and phase trapping of resonant particles, which have been suggested to play an important role in the radiation belt electron dynamics [Albert, 2002;Furuya et al, 2008;Bortnik et al, 2008]. However, the single-wave theories do not take into account the modulation of chorus amplitude, which was shown recently by high resolution observations [Santolík et al, 2004;Tsurutani et al, 2009].…”

The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) on RBSP

“…Non-linear test particle scattering of resonant electrons in such large amplitude waves (Bortnik et al 2008a) indicates that resonant electrons tend to exhibit advective transport towards the loss cone rather than the stochastic diffusive behavior. Such advective scattering could dramatically increase the average rate of resonant electron loss, and may thus be related to the observed electron dropouts (Onsager et al 2007;) during the main phase of magnetic storms.…”

Probability of relativistic electron trapping by parallel and oblique whistler-mode waves in Earth's radiation belts

“…Fig. 7 shows profiles of analytical probabilities (17) calculated with (B5). The particular, but realistic, distribution of wave intensity u(z) displayed in Fig.…”

“…13,15 Such nonlinear interactions include particle trapping and nonlinear scattering (also called phase bunching). 56 Both effects have been investigated for parallel 3,5,17,23,50,62,65 and oblique waves. 7,14,57,59 Although nonlinear scattering is a more widespread effect than particle trapping, the latter can nevertheless be responsible for the rapid acceleration of charged particles 17,22,26 up to very high energy.…”