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Title: Location of intense electromagnetic ion cyclotron (EMIC) wave events relative to the plasmapause: Van Allen Probes observations

In this paper, we have studied the spatial location relative to the plasmapause (PP) of the most intense electromagnetic ion cyclotron (EMIC) waves observed on Van Allen Probes A and B during their first full precession in local time. Most of these waves occurred over an L range of from -1 to +2 R E relative to the PP. Very few events occurred only within 0.1 R E of the PP, and events with a width in L of < 0.2 R E occurred both inside and outside the PP. Wave occurrence was always associated with high densities of ring current ions; plasma density gradients or enhancements were associated with some events but were not dominant factors in determining the sites of wave generation. Storm main and recovery phase events in the dusk sector were often inside the PP, and dayside events during quiet times and compressions of the magnetosphere were more evenly distributed both inside and outside the PP. Superposed epoch analyses of the dependence of wave onset on solar wind dynamic pressure (Psw), the SME (SuperMAG auroral electrojet) index, and the SYM-H index showed that substorm injections and solar wind compressions were temporally closely associated with EMIC wavemore » onset but to an extent that varied with frequency band, magnetic local time, and storm phase, and location relative to the PP. Finally, the fact that increases in SME and Psw were less strongly correlated with events at the PP than with other events might suggest that the occurrence of those events was affected by the density gradient.« less
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [2] ;  [2] ; ORCiD logo [3] ; ORCiD logo [4] ; ORCiD logo [5] ; ORCiD logo [5] ; ORCiD logo [6] ; ORCiD logo [7] ; ORCiD logo [8]
  1. Augsburg College, Minneapolis, MN (United States). Dept. of Physics; Univ. of Iowa, Iowa City, IA (United States). Dept. of Physics and Astronomy
  2. Augsburg College, Minneapolis, MN (United States). Dept. of Physics
  3. Univ. of New Hampshire, Durham, NH (United States). Space Science Center
  4. Dartmouth College, Hanover, NH (United States). Dept. of Physics and Astronomy
  5. Univ. of Minnesota, Minneapolis, MN (United States). School of Physics and Astronomy
  6. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  7. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
  8. The Aerospace Corporation, Los Angeles, CA (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2169-9380; TRN: US1703012
Grant/Contract Number:
AC52-06NA25396; PLR-1341493; ATM-1202267; NNX13AD65G; NAS5-01072
Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Space Physics
Additional Journal Information:
Journal Volume: 122; Journal Issue: 4; Journal ID: ISSN 2169-9380
American Geophysical Union
Research Org:
Augsburg College, Minneapolis, MN (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States); NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
Sponsoring Org:
USDOE; National Science Foundation (NSF); National Aeronautic and Space Administration (NASA)
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; EMIC waves; plasmapause; magnetosphere; plasmasphere; ring current
OSTI Identifier: