Applying Nyquist's method for stability determination to solar wind observations

Kristopher G. Klein, Justin C. Kasper, K. E. Korreck, Michael L. Stevens

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


The role instabilities play in governing the evolution of solar and astrophysical plasmas is a matter of considerable scientific interest. The large number of sources of free energy accessible to such nearly collisionless plasmas makes general modeling of unstable behavior, accounting for the temperatures, densities, anisotropies, and relative drifts of a large number of populations, analytically difficult. We therefore seek a general method of stability determination that may be automated for future analysis of solar wind observations. This work describes an efficient application of the Nyquist instability method to the Vlasov dispersion relation appropriate for hot, collisionless, magnetized plasmas, including the solar wind. The algorithm recovers the familiar proton temperature anisotropy instabilities, as well as instabilities that had been previously identified using fits extracted from in situ observations in Gary et al. (2016). Future proposed applications of this method are discussed.

Original languageEnglish (US)
Pages (from-to)9815-9823
Number of pages9
JournalJournal of Geophysical Research: Space Physics
Issue number10
StatePublished - Oct 2017


  • plasma instabilities
  • solar wind

ASJC Scopus subject areas

  • Geophysics
  • Space and Planetary Science


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