Title: Suppression of Electron Thermal Conduction by Whistler Turbulence in a Sustained Thermal Gradient

Abstract

The dynamics of weakly magnetized collisionless plasmas in the presence of an imposed temperature gradient along an ambient magnetic field is explored with particle-in-cell simulations and modeling. Two thermal reservoirs at different temperatures drive an electron heat flux that destabilizes off-angle whistler-type modes. The whistlers grow to large amplitude, δB/B₀ ≃ 1, and resonantly scatter the electrons, significantly reducing the heat flux. Interestingly, the resulting steady-state heat flux is largely independent of the thermal gradient. The rate of thermal conduction is instead controlled by the finite propagation speed of the whistlers, which act as mobile scattering centers that convect the thermal energy of the hot reservoir. The findings are relevant to thermal transport in high-β astrophysical plasmas such as hot accretion flows and the intracluster medium of galaxy clusters.

Authors:

Roberg-Clark, G. T. ^[1]; Drake, J. F. ^[2]; Reynolds, C. S. ^[2]; Swisdak, M. ^[2]

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+ Show Author Affiliations

1. Univ. of Maryland, College Park, MD (United States)
2. Univ. of Maryland, College Park, MD (United States); Joint Space-Science Inst. (JSI), College Park, MD (United States)

Publication Date:

Fri Jan 19 00:00:00 EST 2018

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)

Sponsoring Org.:

USDOE

OSTI Identifier:

1544335

Alternate Identifier(s):

OSTI ID: 1417508

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review Letters

Additional Journal Information:

Journal Volume: 120; Journal Issue: 3; Journal ID: ISSN 0031-9007

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY