Roles of whistler mode waves and magnetosonic waves in changing the outer radiation belt and the slot region

Abstract

Using the Van Allen Probe long‐term (2013–2015) observations and quasi‐linear simulations of wave‐particle interactions, we examine the combined or competing effects of whistler mode waves (chorus or hiss) and magnetosonic (MS) waves on energetic (<0.5 MeV) and relativistic (>0.5 MeV) electrons inside and outside the plasmasphere. Although whistler mode chorus waves and MS waves can singly or jointly accelerate electrons from the hundreds of keV energy to the MeV energy in the low‐density trough, most of the relativistic electron enhancement events are best correlated with the chorus wave emissions outside the plasmapause. Inside the plasmasphere, intense plasmaspheric hiss can cause the net loss of relativistic electrons via persistent pitch angle scattering, regardless of whether MS waves were present or not. The intense hiss waves not only create the energy‐dependent electron slot region but also remove a lot of the outer radiation belt electrons when the expanding dayside plasmasphere frequently covers the outer zone. Since whistler mode waves (chorus or hiss) can resonate with more electrons than MS waves, they play dominant roles in changing the outer radiation belt and the slot region. However, MS waves can accelerate the energetic electrons below 400 keV and weaken their loss inside the plasmapause. Thus, MS waves and plasmaspheric hiss generate different competing effects on energetic and relativistic electrons in the high‐density plasmasphere.

Self‐Consistent Modeling of Electron Precipitation and Responses in the Ionosphere: Application to Low‐Altitude Energization During Substorms

“…As a result, the two-layer structure in the Pedersen conductivity profile also appears before the storm (Figure 2c). The prestorm two-layer feature at 60 ∘ is a result of wave-particle interactions inside the plasmapause where hiss waves are able to scatter electrons above 10 keV (Li et al, 2015), while the storm time high-energy tail is originated from the chorus wave scattering outside the plasmapause. The prestorm two-layer feature at 60 ∘ is a result of wave-particle interactions inside the plasmapause where hiss waves are able to scatter electrons above 10 keV (Li et al, 2015), while the storm time high-energy tail is originated from the chorus wave scattering outside the plasmapause.…”

Effect of Low‐Harmonic Magnetosonic Waves on the Radiation Belt Electrons Inside the Plasmasphere

“…To evaluate the effect of the LH MS waves on the radiation belt electrons, we used a widely used Gaussian model (e.g., Horne et al, ; Li, Yu, et al, ; Maldonado et al, ) to fit the frequency spectrum distribution of the observed waves, given as follows: …”

“…Recently, wave‐particle interaction is put forward to explain the formation of butterfly distribution far away from the magnetopause. MS waves are believed to be a candidate mechanism responsible for the butterfly formation through Landau resonance (Horne et al, ; Li, Yu, et al, ; Xiao et al, ; Yang et al, ), transit time scattering (Bortnik & Thorne, ; Li et al, ; J. Li, Ni, et al, ; Ni et al, , ), and bounce resonance (Chen et al, ; Li & Tao, ; Maldonado et al, ; Shprits, ; Tao & Li, ). Landau resonance occurs when the parallel phase velocity ( ω / k ∥ ) of waves equals to the electron velocity parallel to background magnetic field ( v ∥ ; Artemyev et al, ) and the minimum resonant energy can be obtained according to the study of Horne et al ().…”

Recent Advancements and Remaining Challenges Associated With Inner Magnetosphere Cross‐Energy/Population Interactions (IMCEPI)

“…While the numerical representation of the geospace system is being greatly improved, better characterization of physics in the near‐Earth environment has also been consistently obtained. For example, the wave dynamics and their impact on plasma dynamics have been analyzed in great detail (e.g., Blum et al, , , ; Fu et al, ; Kim et al, ; W. Li et al, ; J. Li, Ni, et al, ; L. Y. Li, Yu, et al, , ; L. Li, Zhou, et al, ; Ma, Li, et al, ; Murphy et al, ; Shi et al, ; Shprits, Drozdov, et al, ; Turner et al, , ; Usanova et al, ; Wang, Pan, et al, ; Wang, Zhai, et al, ; J. Yu et al ; J.‐C. Zhang et al, ; X.‐J.…”