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Title: Very Oblique Whistler Mode Propagation in the Radiation Belts: Effects of Hot Plasma and Landau Damping

We present that satellite observations of a significant population of very oblique chorus waves in the outer radiation belt have fueled considerable interest in the effects of these waves on energetic electron scattering and acceleration. However, corresponding diffusion rates are extremely sensitive to the refractive index N, controlled by hot plasma effects including Landau damping and wave dispersion modifications by suprathermal (15–100 eV) electrons. A combined investigation of wave and electron distribution characteristics obtained from the Van Allen Probes shows that peculiarities of the measured electron distribution significantly reduce Landau damping, allowing wave propagation with high N ~ 100–200. Further comparing measured refractive indexes with theoretical estimates incorporating hot plasma corrections to the wave dispersion, we provide the first experimental demonstration that suprathermal electrons indeed control the upper limit of the refractive index of highly oblique whistler mode waves. In conclusion, such results further support the importance of incorporating very oblique waves into radiation belt models.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [3] ; ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [4] ; ORCiD logo [4] ; ORCiD logo [4] ; ORCiD logo [5] ; ORCiD logo [6] ; ORCiD logo [7]
  1. Univ. of California, Los Angeles, CA (United States); Boston Univ., MA (United States)
  2. Univ. of California, Los Angeles, CA (United States)
  3. CEA, DAM, DIF, Arpajon (France)
  4. Univ. of Iowa, Iowa City, IA (United States)
  5. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  6. Univ. of New Hampshire, Durham, NH (United States)
  7. Univ. of Minnesota, Minneapolis, MN (United States)
Publication Date:
Report Number(s):
LA-UR-17-29192
Journal ID: ISSN 0094-8276; TRN: US1800914
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 44; Journal Issue: 24; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE; National Aeronautic and Space Administration (NASA)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Heliospheric and Magnetospheric Physics
OSTI Identifier:
1416311