Direct evidence of nonstationary collisionless shocks in space plasmas

Research output: Contribution to journalArticle


  • Andrew P. Dimmock
  • Christopher T. Russell
  • Roald Z. Sagdeev
  • Vladimir Krasnoselskikh
  • Simon N. Walker
  • Christopher Carr
  • Iannis Dandouras
  • C. Philippe Escoubet
  • Natalia Ganushkina
  • Michael Gedalin
  • Yuri Khotyaintsev
  • Homayon Aryan
  • Tuija Pulkkinen

  • Michael A. Balikhin

Research units

  • Swedish Institute of Space Physics
  • University of California at Berkeley
  • Imperial College London
  • University of Michigan, Ann Arbor
  • University of California at Los Angeles
  • University of Maryland
  • University of Sheffield
  • CNRS
  • Universite de Toulouse
  • European Space Agency - ESA
  • Finnish Meteorological Institute
  • Ben-Gurion University of the Negev
  • NASA Goddard Space Flight Center


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.


Original languageEnglish
Article number9926
Number of pages7
JournalScience Advances
Issue number2
Publication statusPublished - Feb 2019
MoE publication typeA1 Journal article-refereed

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