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Title: Comparing simulated and observed EMIC wave amplitudes using in situ Van Allen Probes’ measurements

In this study, we perform a statistical study calculating electromagnetic ion cyclotron (EMIC) wave amplitudes based off in situ plasma measurements taken by the Van Allen Probes’ (1.1–5.8 R e) Helium, Oxygen, Proton, Electron (HOPE) instrument. Calculated wave amplitudes are compared to EMIC waves observed by the Electric and Magnetic Field Instrument Suite and Integrated Science on board the Van Allen Probes during the same period. The survey covers a 22-month period (1 November 2012 to 31 August 2014), a full Van Allen Probe magnetic local time (MLT) precession. The linear theory proxy was used to identify EMIC wave events with plasma conditions favorable for EMIC wave excitation. Two hundred and thirty-two EMIC wave events (103 H +-band and 129 He +-band) were selected for this comparison. Nearly all events selected are observed beyond L = 4. Results show that calculated wave amplitudes exclusively using the in situ HOPE measurements produce amplitudes too low compared to the observed EMIC wave amplitudes. Hot proton anisotropy (Ahp) distributions are asymmetric in MLT within the inner (L < 7) magnetosphere with peak (minimum) A hp, ~0.81 to 1.00 (~0.62), observed in the dawn (dusk), 0000 < MLT ≤ 1200 (1200 < MLT ≤more » 2400), sectors. Measurements of A hp are found to decrease in the presence of EMIC wave activity. A hp amplification factors are determined and vary with respect to EMIC wave-band and MLT. Lastly, He +-band events generally require double (quadruple) the measured A hp for the dawn (dusk) sector to reproduce the observed EMIC wave amplitudes.« less
 [1] ; ORCiD logo [2] ;  [1] ;  [1] ;  [1] ; ORCiD logo [3] ; ORCiD logo [3] ;  [1] ;  [4] ;  [5] ;  [6]
  1. Univ. of New Hampshire, Durham, NH (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); The New Mexico Consortium, Los Alamos, NM (United States)
  4. Univ. of Iowa, Iowa City, IA (United States)
  5. Univ. of California, Los Angeles, CA (United States)
  6. Univ. of California, Los Angeles, CA (United States) ; University of Potsdam (Germany)
Publication Date:
Report Number(s):
Journal ID: ISSN 1364-6826
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Atmospheric and Solar-Terrestrial Physics
Additional Journal Information:
Journal Name: Journal of Atmospheric and Solar-Terrestrial Physics; Journal ID: ISSN 1364-6826
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
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 58 GEOSCIENCES; EMIC waves; Van Allen Probes; Linear theory; Wave generation
OSTI Identifier: