Rippled Quasiperpendicular Shock Observed by the Magnetospheric Multiscale Spacecraft.

Andreas Johlander ,B Lavraud,A Vaivads,Y Saito,W Magnes,Stefano Markidis ,R J Strangeway ,R B Torbert ,L A Avanov ,C J Pollock ,W R Paterson ,Ferdinand Plaschke ,R E Ergun ,Göran Marklund ,D J Gershman ,Per‐Arne Lindqvist ,Yuri Khotyaintsev ,H Y Wei ,B L Giles ,Ivy Bo Peng ,Steven J Schwartz ,Imogen Gingell ,J Dorelli ,C T Russell ,J L Burch

doi:10.1103/physrevlett.117.165101

Abstract

Collisionless shock nonstationarity arising from microscale physics influences shock structure and particle acceleration mechanisms. Nonstationarity has been difficult to quantify due to the small spatial and temporal scales. We use the closely spaced (subgyroscale), high-time-resolution measurements from one rapid crossing of Earth's quasiperpendicular bow shock by the Magnetospheric Multiscale (MMS) spacecraft to compare competing nonstationarity processes. Using MMS's high-cadence kinetic plasma measurements, we show that the shock exhibits nonstationarity in the form of ripples.

Highlights

Collisionless shock nonstationarity arising from microscale physics influences shock structure and particle acceleration mechanisms
Using Magnetospheric Multiscale (MMS)’s high-cadence kinetic plasma measurements, we show that the shock exhibits nonstationarity in the form of ripples
Collisionless shocks are abundant in astrophysical plasmas such as around supernova remnants and in our solar system as planetary bow shocks and interplanetary shocks

Summary

Multiscale Spacecraft

Collisionless shock nonstationarity arising from microscale physics influences shock structure and particle acceleration mechanisms. Using MMS’s high-cadence kinetic plasma measurements, we show that the shock exhibits nonstationarity in the form of ripples. Acceleration, is a long-standing issue in shock physics It was theorized by Auer, Hurwitz, and Kilb [3] and demonstrated in laboratory plasmas [4]. Simulations by Lowe and Burgess [10] showed that the surface of a quasiperpendicular shock supports ripples that propagate along the shock front. Such ripples are potential sites of electron acceleration [11] and influence the ion dynamics [12,13]. Moullard et al [14] presented evidence of such ripples by exploiting a slow, 0031-9007=16=117(16)=165101(5)

Published by the American Physical Society

Magnetic field magnitude B

The average period of the ripples in the NIF is