skip to main content

Title: Nonlinear and linear timescales near kinetic scales in solar wind turbulence

The application of linear kinetic treatments to plasma waves, damping, and instability requires favorable inequalities between the associated linear timescales and timescales for nonlinear (e.g., turbulence) evolution. In the solar wind these two types of timescales may be directly compared using standard Kolmogorov-style analysis and observational data. The estimated local (in scale) nonlinear magnetohydrodynamic cascade times, evaluated as relevant kinetic scales are approached, remain slower than the cyclotron period, but comparable to or faster than the typical timescales of instabilities, anisotropic waves, and wave damping. The variation with length scale of the turbulence timescales is supported by observations and simulations. On this basis the use of linear theory—which assumes constant parameters to calculate the associated kinetic rates—may be questioned. It is suggested that the product of proton gyrofrequency and nonlinear time at the ion gyroscales provides a simple measure of turbulence influence on proton kinetic behavior.
Authors:
; ;  [1] ;  [2] ; ;  [3] ; ;  [4] ;  [5] ; ;  [6]
  1. Department of Physics and Astronomy, University of Delaware, DE 19716 (United States)
  2. Department of Mathematics, University of Waikato, Hamilton (New Zealand)
  3. Centre for Fusion, Space, and Astrophysics, University of Warwick, Coventry CV4 7AL (United Kingdom)
  4. Dipartimento di Fisica, Università della Calabria, I-87036 Cosenza (Italy)
  5. Space Sciences Institute, Boulder, CO 80301 (United States)
  6. Sciberquest, Inc., Del Mar, CA 92014 (United States)
Publication Date:
OSTI Identifier:
22365445
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 790; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; COMPARATIVE EVALUATIONS; CYCLOTRONS; EVOLUTION; GYROFREQUENCY; INSTABILITY; MAGNETOHYDRODYNAMICS; PLASMA WAVES; PROTONS; SIMULATION; SOLAR WIND; SUN; TURBULENCE