Direct evidence of nonstationary collisionless shocks in space plasmas

Loading...
Thumbnail Image
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This publication is imported from Aalto University research portal.
View publication in the Research portal
View/Open full text file from the Research portal
Date
2019-02
Major/Subject
Mcode
Degree programme
Language
en
Pages
7
Series
Science Advances, Volume 5, issue 2
Abstract
Collisionless shocks are ubiquitous throughout the universe: around stars, supernova remnants, active galactic nuclei, binary systems, comets, and planets. Key information is carried by electromagnetic emissions from particles accelerated by high Mach number collisionless shocks. These shocks are intrinsically nonstationary, and the characteristic physical scales responsible for particle acceleration remain unknown. Quantifying these scales is crucial, as it affects the fundamental process of redistributing upstream plasma kinetic energy into other degrees of freedom-particularly electron thermalization. Direct in situ measurements of nonstationary shock dynamics have not been reported. Thus, the model that best describes this process has remained unknown. Here, we present direct evidence demonstrating that the transition to nonstationarity is associated with electron-scale field structures inside the shock ramp.
Description
Keywords
WAVES OBSERVED UPSTREAM, PERPENDICULAR SHOCKS, MACH NUMBER, BOW SHOCK
Other note
Citation
Dimmock , A P , Russell , C T , Sagdeev , R Z , Krasnoselskikh , V , Walker , S N , Carr , C , Dandouras , I , Escoubet , C P , Ganushkina , N , Gedalin , M , Khotyaintsev , Y , Aryan , H , Pulkkinen , T & Balikhin , M A 2019 , ' Direct evidence of nonstationary collisionless shocks in space plasmas ' , Science Advances , vol. 5 , no. 2 , 9926 . https://doi.org/10.1126/sciadv.aau9926