Instability of Agyrotropic Electron Beams near the Electron Diffusion Region

D. B. Graham, Yu. V. Khotyaintsev, A. Vaivads, C. Norgren, M. André, J. M. Webster, J. L. Burch, P.-A. Lindqvist, R. E. Ergun, R. B. Torbert, W. R. Paterson, D. J. Gershman, B. L. Giles, W. Magnes, and C. T. Russell

Phys. Rev. Lett. 119, 025101 – Published 13 July 2017

Abstract

During a magnetopause crossing the Magnetospheric Multiscale spacecraft encountered an electron diffusion region (EDR) of asymmetric reconnection. The EDR is characterized by agyrotropic beam and crescent electron distributions perpendicular to the magnetic field. Intense upper-hybrid (UH) waves are found at the boundary between the EDR and magnetosheath inflow region. The UH waves are generated by the agyrotropic electron beams. The UH waves are sufficiently large to contribute to electron diffusion and scattering, and are a potential source of radio emission near the EDR. These results provide observational evidence of wave-particle interactions at an EDR, and suggest that waves play an important role in determining the electron dynamics.

Received 3 December 2016

DOI:https://doi.org/10.1103/PhysRevLett.119.025101

Physics Subject Headings (PhySH)

Beam-plasma instability Magnetic reconnection

Magnetopause

Satellite data analysis

Plasma Physics

Authors & Affiliations

D. B. Graham¹, Yu. V. Khotyaintsev¹, A. Vaivads¹, C. Norgren^1,2, M. André¹, J. M. Webster³, J. L. Burch⁴, P.-A. Lindqvist⁵, R. E. Ergun⁶, R. B. Torbert⁷, W. R. Paterson⁸, D. J. Gershman^8,9, B. L. Giles⁸, W. Magnes¹⁰, and C. T. Russell¹¹

¹Swedish Institute of Space Physics, Uppsala SE-75121, Sweden
²Department of Physics and Astronomy, Uppsala University, Uppsala SE-75121, Sweden
³Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
⁴Southwest Research Institute, San Antonio, Texas 78238, USA
⁵Space and Plasma Physics, School of Electrical Engineering, KTH Royal Institute of Technology, Stockholm SE-11428, Sweden
⁶Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA
⁷Space Science Center, University of New Hampshire, Durham, New Hampshire 03824, USA
⁸NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
⁹Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA
¹⁰Space Research Institute, Austrian Academy of Sciences, Graz 8042, Austria
¹¹Department of Earth and Space Sciences, University of California, Los Angeles, California 90095, USA

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Issue

Vol. 119, Iss. 2 — 14 July 2017

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