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Title: Correlated Pc4-5 ULF waves, whistler-mode chorus, and pulsating aurora observed by the Van Allen Probes and ground-based systems

Theory and observations have linked equatorial VLF waves with pulsating aurora for decades, invoking the process of pitch angle scattering of tens of keV electrons in the equatorial magnetosphere. Recently published satellite studies have strengthened this argument, by showing strong correlation between pulsating auroral patches and both lower-band chorus and tens of keV electron modulation in the vicinity of geosynchronous orbit. Additionally, a previous link has been made between Pc4–5 compressional pulsations and modulation of whistler-mode chorus using Time History of Events and Macroscale Interactions during Substorms. In the current study, we present simultaneous in situ observations of structured chorus waves and an apparent field line resonance (in the Pc4–5 range) as a result of a substorm injection, observed by Van Allen Probes, along with ground-based observations of pulsating aurora. We demonstrate the likely scenario being one of substorm-driven Pc4–5 ULF pulsations modulating chorus waves, and thus providing the driver for pulsating particle precipitation into the Earth's atmosphere. Interestingly, the modulated chorus wave and ULF wave periods are well correlated, with chorus occurring at half the periodicity of the ULF waves. We also show, for the first time, a particular few-Hz modulation of individual chorus elements that coincides with themore » same modulation in a nearby pulsating aurora patch. As a result, such modulation has been noticed as a high-frequency component in ground-based camera data of pulsating aurora for decades and may be a result of nonlinear chorus wave interactions in the equatorial region.« less
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [1] ;  [4] ;  [5] ;  [1] ;  [6] ;  [5] ;  [5] ;  [7] ;  [8] ;  [9] ;  [2] ;  [10]
  1. Univ. of Colorado, Boulder, CO (United States)
  2. Univ. of New Hampshire, Durham, NH (United States)
  3. The Johns Hopkins Univ. Applied Physics Laboratory, Laurel, MD (United States)
  4. Univ. of Maryland, College Park, MD (United States); NASA GSFC, Greenbelt, MD (United States)
  5. Univ. of Calgary, Calgary, AB (Canada)
  6. Aerospace Corporation, El Segundo, CA (United States)
  7. Univ. of Iowa, Iowa City, IA (United States)
  8. New Mexico Consortium, Los Alamos, NM (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  9. NASA GSFC, Greenbelt, MD (United States)
  10. Univ. of Minnesota, Minneapolis, MN (United States)
Publication Date:
OSTI Identifier:
1236778
Report Number(s):
LA-UR--15-27788
Journal ID: ISSN 2169-9380
Grant/Contract Number:
contract 428 967399; contract NAS5-01072; NNX13AO43H; NNX14AB97G; AGS-1456161; AGS-1456129; AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Space Physics
Additional Journal Information:
Journal Volume: 120; Journal Issue: 10; Journal ID: ISSN 2169-9380
Publisher:
American Geophysical Union
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES