Direct evidence of nonstationary collisionless shocks in space plasmas

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

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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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.

Original languageEnglish
Article number9926
Number of pages7
JournalScience Advances
Volume5
Issue number2
DOIs
Publication statusPublished - Feb 2019
MoE publication typeA1 Journal article-refereed

Keywords

  • WAVES OBSERVED UPSTREAM
  • PERPENDICULAR SHOCKS
  • MACH NUMBER
  • BOW SHOCK

Projects

The turbulent magnetosheath: the impact on magnetospheric and radiation belt plasma properties

Pulkkinen, T. & Dimmock, A.

01/09/201531/05/2018

Project: Academy of Finland: Other research funding

Cite this

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, 5(2), [9926]. https://doi.org/10.1126/sciadv.aau9926