Observing the prevalence of thin current sheets downstream of Earth's bow shock

Abstract

Actively reconnecting, thin current sheets have been observed both within the transition region of Earth's bow shock and far downstream into the magnetosheath. Irrespective of whether these structures arise due to shock processes or turbulent dissipation, they are expected to contribute to particle heating and acceleration within their respective regions. In order to assess the prevalence of thin current sheets in the magnetosheath, we examine shock crossings and extended magnetosheath intervals recorded by the magnetospheric multiscale mission (MMS). For each magnetosheath interval, we quantify the prevalence of current sheets in that region of space using: a one-dimensional measure of structures per unit length of observed plasma, a packing factor corresponding to the fraction of time the spacecraft are within current structures, and a three-dimensional measure requiring an estimate of the number of current sheets within an associated volume. We estimate that volume by considering the three-dimensional cone over which Alfvén and magnetoacoustic waves can propagate during each interval. Using 25 extended magnetosheath intervals observed by MMS, we perform our analysis for different locations in the magnetosheath and for different solar wind conditions. We find that the number density of current sheets is higher toward the magnetosheath flanks, that it reduces as a power law with distance from the bow shock, and that it is not strongly influenced by the properties of the upstream bow shock.

More information

Identifiers

ORCID for Imogen Gingell: orcid.org/0000-0003-2218-1909

Catalogue record

Export record

Altmetrics