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The nonlinear behavior of whistler waves at the reconnecting dayside magnetopause as observed by the Magnetospheric Multiscale mission: A case study
Author(s) -
Wilder F. D.,
Ergun R. E.,
Newman D. L.,
Goodrich K. A.,
Trattner K. J.,
Goldman M. V.,
Eriksson S.,
Jaynes A. N.,
Leonard T.,
Malaspina D. M.,
Ahmadi N.,
Schwartz S. J.,
Burch J. L.,
Torbert R. B.,
Argall M. R.,
Giles B. L.,
Phan T. D.,
Le Contel O.,
Graham D. B.,
Khotyaintsev Yu V.,
Strangeway R. J.,
Russell C. T.,
Magnes W.,
Plaschke F.,
Lindqvist P.A.
Publication year - 2017
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2017ja024062
Subject(s) - whistler , physics , magnetopause , magnetosphere , poynting vector , computational physics , geophysics , plasmasphere , field line , magnetosheath , pitch angle , electron , electric field , anisotropy , electron precipitation , magnetic field , optics , quantum mechanics
We show observations of whistler mode waves in both the low‐latitude boundary layer (LLBL) and on closed magnetospheric field lines during a crossing of the dayside reconnecting magnetopause by the Magnetospheric Multiscale (MMS) mission on 11 October 2015. The whistlers in the LLBL were on the electron edge of the magnetospheric separatrix and exhibited high propagation angles with respect to the background field, approaching 40°, with bursty and nonlinear parallel electric field signatures. The whistlers in the closed magnetosphere had Poynting flux that was more field aligned. Comparing the reduced electron distributions for each event, the magnetospheric whistlers appear to be consistent with anisotropy‐driven waves, while the distribution in the LLBL case includes anisotropic backward resonant electrons and a forward resonant beam at near half the electron‐Alfvén speed. Results are compared with the previously published observations by MMS on 19 September 2015 of LLBL whistler waves. The observations suggest that whistlers in the LLBL can be both beam and anisotropy driven, and the relative contribution of each might depend on the distance from the X line.