MMS observations of electron scale magnetic cavity embedded in proton scale magnetic cavity

H Liu; Q-G Zong; H Zhang; C J Xiao; Q Q Shi; S T Yao; J S He; X-Z Zhou; C Pollock; W J Sun; G Le; J L Burch; R Rankin

doi:10.1038/s41467-019-08971-y

MMS observations of electron scale magnetic cavity embedded in proton scale magnetic cavity

Nat Commun. 2019 Mar 4;10(1):1040. doi: 10.1038/s41467-019-08971-y.

Authors

H Liu^{1

2}, Q-G Zong³, H Zhang², C J Xiao⁴, Q Q Shi⁵, S T Yao⁵, J S He¹, X-Z Zhou¹, C Pollock⁶, W J Sun⁷, G Le⁸, J L Burch⁹, R Rankin¹⁰

Affiliations

¹ Institute of Space Physics and Applied Technology, Peking University, Beijing, 100871, China.
² Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA.
³ Institute of Space Physics and Applied Technology, Peking University, Beijing, 100871, China. qgzong@pku.edu.cn.
⁴ State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing, 100871, China.
⁵ Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai, 264209, China.
⁶ Denali Scientific, 3771 Mariposa Lane, Fairbanks, AK, 99709, USA.
⁷ Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
⁸ NASA, Goddard Space Flight Center, Greenbelt, MD, 20771, USA.
⁹ Southwest Research Institute, San Antonio, TX, 78238, USA.
¹⁰ Department of Physics, University of Alberta, Edmonton, T6G 2G7, AB, Canada.

Abstract

Magnetic cavities (sometimes referred to as magnetic holes) at electron kinetic scale are thought to be one of the extremely small intermittent structures formed in magnetized turbulent plasmas, where the turbulence energy cascaded down to electron scale may finally be dissipated and consequently energize the electrons. However, the geometry and formation of these structures remain not definitively resolved. Here we discuss an electron scale magnetic cavity embedded in a proton scale magnetic cavity observed by the MMS spacecraft in the magnetosheath. By applying an innovative particle sounding technique, we directly depict the boundary of the electron scale magnetic cavity and uncover the geometry. We find that this structure is nearly circular with a radius of 10.0 km and its formation is due to the diamagnetic current. Investigation of the electron scale structure is only recently made possible by the high spatial and temporal resolution provided by MMS observations.

Publication types

Research Support, Non-U.S. Gov't