Direct observations of energy transfer from resonant electrons to whistler-mode waves in magnetosheath of Earth

N Kitamura; T Amano; Y Omura; S A Boardsen; D J Gershman; Y Miyoshi; M Kitahara; Y Katoh; H Kojima; S Nakamura; M Shoji; Y Saito; S Yokota; B L Giles; W R Paterson; C J Pollock; A C Barrie; D G Skeberdis; S Kreisler; O Le Contel; C T Russell; R J Strangeway; P-A Lindqvist; R E Ergun; R B Torbert; J L Burch

doi:10.1038/s41467-022-33604-2

Direct observations of energy transfer from resonant electrons to whistler-mode waves in magnetosheath of Earth

Nat Commun. 2022 Oct 28;13(1):6259. doi: 10.1038/s41467-022-33604-2.

Authors

N Kitamura^{1

2}, T Amano³, Y Omura⁴, S A Boardsen^{5

6}, D J Gershman⁵, Y Miyoshi⁷, M Kitahara⁸, Y Katoh⁸, H Kojima⁴, S Nakamura⁷, M Shoji⁷, Y Saito⁹, S Yokota¹⁰, B L Giles⁵, W R Paterson⁵, C J Pollock¹¹, A C Barrie^{5

12}, D G Skeberdis^{5

13}, S Kreisler^{5

12}, O Le Contel¹⁴, C T Russell¹⁵, R J Strangeway¹⁵, P-A Lindqvist¹⁶, R E Ergun¹⁷, R B Torbert^{18

19}, J L Burch¹⁹

Affiliations

¹ Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan. kitamura@isee.nagoya-u.ac.jp.
² Department of Earth and Planetary Science, Graduate School of Science, the University of Tokyo, Tokyo, Japan. kitamura@isee.nagoya-u.ac.jp.
³ Department of Earth and Planetary Science, Graduate School of Science, the University of Tokyo, Tokyo, Japan.
⁴ Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan.
⁵ NASA Goddard Space Flight Center, Greenbelt, MD, USA.
⁶ Goddard Planetary Heliophysics Institute, University of Maryland, Baltimore County, MD, USA.
⁷ Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan.
⁸ Department of Geophysics, Graduate school of Science, Tohoku University, Sendai, Japan.
⁹ Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan.
¹⁰ Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Japan.
¹¹ Denali Scientific, Fairbanks, AK, USA.
¹² Aurora Engineering, Potomac, MD, USA.
¹³ a.i. solutions Inc, Lanham, MD, USA.
¹⁴ Laboratoire de Physique des Plasmas, CNRS/Sorbonne Université/Université Paris-Saclay/Observatoire de Paris/Ecole Polytechnique Institut Polytechnique de Paris, Paris, France.
¹⁵ Department of Earth, Planetary, and Space Science, University of California, Los Angeles, CA, USA.
¹⁶ Royal Institute of Technology, Stockholm, Sweden.
¹⁷ Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, USA.
¹⁸ Department of Physics, University of New Hampshire, Durham, NH, USA.
¹⁹ Southwest Research Institute, San Antonio, TX, USA.

Abstract

Electromagnetic whistler-mode waves in space plasmas play critical roles in collisionless energy transfer between the electrons and the electromagnetic field. Although resonant interactions have been considered as the likely generation process of the waves, observational identification has been extremely difficult due to the short time scale of resonant electron dynamics. Here we show strong nongyrotropy, which rotate with the wave, of cyclotron resonant electrons as direct evidence for the locally ongoing secular energy transfer from the resonant electrons to the whistler-mode waves using ultra-high temporal resolution data obtained by NASA's Magnetospheric Multiscale (MMS) mission in the magnetosheath. The nongyrotropic electrons carry a resonant current, which is the energy source of the wave as predicted by the nonlinear wave growth theory. This result proves the nonlinear wave growth theory, and furthermore demonstrates that the degree of nongyrotropy, which cannot be predicted even by that nonlinear theory, can be studied by observations.

Abstract

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