Van Allen Probes observations linking radiation belt electrons to chorus waves during 2014 multiple storms

Si Liu, Fuliang Xiao, Chang Yang, Yihua He, Qinghua Zhou, C. A. Kletzing, W. S. Kurth, G. B. Hospodarsky, H. E. Spence, G. D. Reeves, H. O. Funsten, J. B. Blake, D. N. Baker, J. R. Wygant

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

During 18 February to 2 March 2014, the Van Allen Probes encountered multiple geomagnetic storms and simultaneously observed intensified chorus and hiss waves. During this period, there were substantial enhancements in fluxes of energetic (53.8-108.3 keV) and relativistic (2-3.6 MeV) electrons. Chorus waves were excited at locations L = 4-6.2 after the fluxes of energetic were greatly enhanced, with a lower frequency band and wave amplitudes ∼20-100 pT. Strong hiss waves occurred primarily in the main phases or below the location L = 4 in the recovery phases. Relativistic electron fluxes decreased in the main phases due to the adiabatic (e.g., the magnetopause shadowing) or nonadiabatic (hiss-induced scattering) processes. In the recovery phases, relativistic electron fluxes either increased in the presence of enhanced chorus or remained unchanged in the absence of strong chorus or hiss. The observed relativistic electron phase space density peaked around L∗ = 4.5, characteristic of local acceleration. This multiple-storm period reveals a typical picture that chorus waves are excited by the energetic electrons at first and then produce efficient acceleration of relativistic electrons. This further demonstrates that the interplay between both competing mechanisms of chorus-driven acceleration and hiss-driven scattering often occurs in the outer radiation belts.

Original languageEnglish (US)
Pages (from-to)938-948
Number of pages11
JournalJournal of Geophysical Research: Space Physics
Volume120
Issue number2
DOIs
StatePublished - Feb 2015

Bibliographical note

Publisher Copyright:
©2015. American Geophysical Union. All Rights Reserved.

Keywords

  • RBSP results
  • chorus and hiss excitation
  • energetic electron flux
  • relativistic electron acceleration
  • wave-particle interaction

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