Noise-induced magnetic field saturation in kinetic simulations

J. Juno, M. M. Swisdak, J. M. Tenbarge, V. Skoutnev, A. Hakim

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Monte Carlo methods are often employed to numerically integrate kinetic equations, such as the particle-in-cell method for the plasma kinetic equation, but these methods suffer from the introduction of counting noise to the solution. We report on a cautionary tale of counting noise modifying the nonlinear saturation of kinetic instabilities driven by unstable beams of plasma. We find a saturated magnetic field in under-resolved particle-in-cell simulations due to the sampling error in the current density. The noise-induced magnetic field is anomalous, as the magnetic field damps away in continuum kinetic and increased particle count particle-in-cell simulations. This modification of the saturated state has implications for a broad array of astrophysical phenomena beyond the simple plasma system considered here, and it stresses the care that must be taken when using particle methods for kinetic equations.

Original languageEnglish (US)
Article number175860401
JournalJournal of Plasma Physics
StateAccepted/In press - 2020

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics


  • astrophysical plasmas
  • plasma simulation
  • space plasma physics


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