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Title: SUBPROTON-SCALE CASCADES IN SOLAR WIND TURBULENCE: DRIVEN HYBRID-KINETIC SIMULATIONS

Abstract

A long-lasting debate in space plasma physics concerns the nature of subproton-scale fluctuations in solar wind (SW) turbulence. Over the past decade, a series of theoretical and observational studies were presented in favor of either kinetic Alfvén wave (KAW) or whistler turbulence. Here, we investigate numerically the nature of the subproton-scale turbulent cascade for typical SW parameters by means of unprecedented high-resolution simulations of forced hybrid-kinetic turbulence in two real-space and three velocity-space dimensions. Our analysis suggests that small-scale turbulence in this model is dominated by KAWs at β ≳ 1 and by magnetosonic/whistler fluctuations at lower β . The spectral properties of the turbulence appear to be in good agreement with theoretical predictions. A tentative interpretation of this result in terms of relative changes in the damping rates of the different waves is also presented. Overall, the results raise interesting new questions about the properties and variability of subproton-scale turbulence in the SW, including its possible dependence on the plasma β , and call for detailed and extensive parametric explorations of driven kinetic turbulence in three dimensions.

Authors:
 [1];  [2]; ;  [3]
  1. Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany)
  2. Physics Department “E. Fermi,” University of Pisa, Largo B. Pontecorvo 3, I-56127 Pisa (Italy)
  3. Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)
Publication Date:
OSTI Identifier:
22654340
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 822; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALFVEN WAVES; DAMPING; EXPLORATION; FLUCTUATIONS; FORECASTING; KINETICS; PLASMA; RESOLUTION; SIMULATION; SOLAR WIND; SPACE; TURBULENCE; VELOCITY; WHISTLERS

Citation Formats

Cerri, S. S., Califano, F., Jenko, F., Told, D., and Rincon, F., E-mail: sscerr@ipp.mpg.de, E-mail: silvio.cerri@df.unipi.it. SUBPROTON-SCALE CASCADES IN SOLAR WIND TURBULENCE: DRIVEN HYBRID-KINETIC SIMULATIONS. United States: N. p., 2016. Web. doi:10.3847/2041-8205/822/1/L12.
Cerri, S. S., Califano, F., Jenko, F., Told, D., & Rincon, F., E-mail: sscerr@ipp.mpg.de, E-mail: silvio.cerri@df.unipi.it. SUBPROTON-SCALE CASCADES IN SOLAR WIND TURBULENCE: DRIVEN HYBRID-KINETIC SIMULATIONS. United States. https://doi.org/10.3847/2041-8205/822/1/L12
Cerri, S. S., Califano, F., Jenko, F., Told, D., and Rincon, F., E-mail: sscerr@ipp.mpg.de, E-mail: silvio.cerri@df.unipi.it. Sun . "SUBPROTON-SCALE CASCADES IN SOLAR WIND TURBULENCE: DRIVEN HYBRID-KINETIC SIMULATIONS". United States. https://doi.org/10.3847/2041-8205/822/1/L12.
@article{osti_22654340,
title = {SUBPROTON-SCALE CASCADES IN SOLAR WIND TURBULENCE: DRIVEN HYBRID-KINETIC SIMULATIONS},
author = {Cerri, S. S. and Califano, F. and Jenko, F. and Told, D. and Rincon, F., E-mail: sscerr@ipp.mpg.de, E-mail: silvio.cerri@df.unipi.it},
abstractNote = {A long-lasting debate in space plasma physics concerns the nature of subproton-scale fluctuations in solar wind (SW) turbulence. Over the past decade, a series of theoretical and observational studies were presented in favor of either kinetic Alfvén wave (KAW) or whistler turbulence. Here, we investigate numerically the nature of the subproton-scale turbulent cascade for typical SW parameters by means of unprecedented high-resolution simulations of forced hybrid-kinetic turbulence in two real-space and three velocity-space dimensions. Our analysis suggests that small-scale turbulence in this model is dominated by KAWs at β ≳ 1 and by magnetosonic/whistler fluctuations at lower β . The spectral properties of the turbulence appear to be in good agreement with theoretical predictions. A tentative interpretation of this result in terms of relative changes in the damping rates of the different waves is also presented. Overall, the results raise interesting new questions about the properties and variability of subproton-scale turbulence in the SW, including its possible dependence on the plasma β , and call for detailed and extensive parametric explorations of driven kinetic turbulence in three dimensions.},
doi = {10.3847/2041-8205/822/1/L12},
url = {https://www.osti.gov/biblio/22654340}, journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 822,
place = {United States},
year = {2016},
month = {5}
}