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Title: Generation of lower and upper bands of electrostatic electron cyclotron harmonic waves in the Van Allen radiation belts

Abstract

Electrostatic electron cyclotron harmonic (ECH) waves generated by the electron loss cone distribution can produce efficient scattering loss of plasma sheet electrons, which has a significant effect on the dynamics in the outer magnetosphere. Here we report two ECH emission events around the same location L≈ 5.7–5.8, MLT ≈ 12 from Van Allen Probes on 11 February (event A) and 9 January 2014 (event B), respectively. The spectrum of ECH waves was centered at the lower half of the harmonic bands during event A, but the upper half during event B. The observed electron phase space density in both events is fitted by the subtracted bi-Maxwellian distribution, and the fitting functions are used to evaluate the local growth rates of ECH waves based on a linear theory for homogeneous plasmas. ECH waves are excited by the loss cone instability of 50 eV–1 keV electrons in the lower half of harmonic bands in the low-density plasmasphere in event A, and 1–10 keV electrons in the upper half of harmonic bands in a relatively high-density region in event B. Here, the current results successfully explain observations and provide a first direct evidence on how ECH waves are generated in the lower andmore » upper half of harmonic frequency bands.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [4]; ORCiD logo [4]
  1. Changsha Univ. of Science and Technology, Changsha (China)
  2. Univ. of Colorado, Boulder, CO (United States)
  3. Univ. of New Hampshire, Durham, NH (United States)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
National Aeronautic and Space Administration (NASA); USDOE
OSTI Identifier:
1402656
Report Number(s):
LA-UR-17-28037
Journal ID: ISSN 0094-8276; TRN: US1702891
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 44; Journal Issue: 11; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; Heliospheric and Magnetospheric Physics; ECH waves; wave-particle interaction; RBSP results

Citation Formats

Zhou, Qinghua, Xiao, Fuliang, Yang, Chang, Liu, Si, He, Yihua, Baker, D. N., Spence, H. E., Reeves, Geoffrey D., and Funsten, Herbert O. Generation of lower and upper bands of electrostatic electron cyclotron harmonic waves in the Van Allen radiation belts. United States: N. p., 2017. Web. doi:10.1002/2017GL073051.
Zhou, Qinghua, Xiao, Fuliang, Yang, Chang, Liu, Si, He, Yihua, Baker, D. N., Spence, H. E., Reeves, Geoffrey D., & Funsten, Herbert O. Generation of lower and upper bands of electrostatic electron cyclotron harmonic waves in the Van Allen radiation belts. United States. doi:10.1002/2017GL073051.
Zhou, Qinghua, Xiao, Fuliang, Yang, Chang, Liu, Si, He, Yihua, Baker, D. N., Spence, H. E., Reeves, Geoffrey D., and Funsten, Herbert O. 2017. "Generation of lower and upper bands of electrostatic electron cyclotron harmonic waves in the Van Allen radiation belts". United States. doi:10.1002/2017GL073051.
@article{osti_1402656,
title = {Generation of lower and upper bands of electrostatic electron cyclotron harmonic waves in the Van Allen radiation belts},
author = {Zhou, Qinghua and Xiao, Fuliang and Yang, Chang and Liu, Si and He, Yihua and Baker, D. N. and Spence, H. E. and Reeves, Geoffrey D. and Funsten, Herbert O.},
abstractNote = {Electrostatic electron cyclotron harmonic (ECH) waves generated by the electron loss cone distribution can produce efficient scattering loss of plasma sheet electrons, which has a significant effect on the dynamics in the outer magnetosphere. Here we report two ECH emission events around the same location L≈ 5.7–5.8, MLT ≈ 12 from Van Allen Probes on 11 February (event A) and 9 January 2014 (event B), respectively. The spectrum of ECH waves was centered at the lower half of the harmonic bands during event A, but the upper half during event B. The observed electron phase space density in both events is fitted by the subtracted bi-Maxwellian distribution, and the fitting functions are used to evaluate the local growth rates of ECH waves based on a linear theory for homogeneous plasmas. ECH waves are excited by the loss cone instability of 50 eV–1 keV electrons in the lower half of harmonic bands in the low-density plasmasphere in event A, and 1–10 keV electrons in the upper half of harmonic bands in a relatively high-density region in event B. Here, the current results successfully explain observations and provide a first direct evidence on how ECH waves are generated in the lower and upper half of harmonic frequency bands.},
doi = {10.1002/2017GL073051},
journal = {Geophysical Research Letters},
number = 11,
volume = 44,
place = {United States},
year = 2017,
month = 5
}

Journal Article:
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