Observations of Electromagnetic Electron Holes and Evidence of Cherenkov Whistler Emission

Konrad Steinvall; Yuri V Khotyaintsev; Daniel B Graham; Andris Vaivads; Olivier Le Contel; Christopher T Russell

doi:10.1103/PhysRevLett.123.255101

Observations of Electromagnetic Electron Holes and Evidence of Cherenkov Whistler Emission

Phys Rev Lett. 2019 Dec 20;123(25):255101. doi: 10.1103/PhysRevLett.123.255101.

Authors

Konrad Steinvall^{1

2}, Yuri V Khotyaintsev¹, Daniel B Graham¹, Andris Vaivads³, Olivier Le Contel⁴, Christopher T Russell⁵

Affiliations

¹ Swedish Institute of Space Physics, Uppsala 75121, Sweden.
² Space and Plasma Physics, Department of Physics and Astronomy, Uppsala University, Uppsala 75120, Sweden.
³ Division of Space and Plasma Physics, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm 11428, Sweden.
⁴ Laboratoire de Physique des Plasmas, CNRS/Ecole Polytechnique/Sorbonne Université/Univ. Paris Sud/Observatoire de Paris, Paris, F-75252 Paris Cedex 05, France.
⁵ Department of Earth and Space Sciences, University of California, Los Angeles, California 90095, USA.

PMID: 31922784
DOI: 10.1103/PhysRevLett.123.255101

Abstract

We report observations of electromagnetic electron holes (EHs). We use multispacecraft analysis to quantify the magnetic field contributions of three mechanisms: the Lorentz transform, electron drift within the EH, and Cherenkov emission of whistler waves. The first two mechanisms account for the observed magnetic fields for slower EHs, while for EHs with speeds approaching half the electron Alfvén speed, whistler waves excited via the Cherenkov mechanism dominate the perpendicular magnetic field. The excited whistler waves are kinetically damped and typically confined within the EHs.