Dynamo in Weakly Collisional Nonmagnetized Plasmas Impeded by Landau Damping of Magnetic Fields
Artikel i vetenskaplig tidskrift, 2020

We perform fully kinetic simulations of flows known to produce dynamo in magnetohydrodynamics (MHD), considering scenarios with low Reynolds number and high magnetic Prandtl number, relevant for galaxy cluster scale fluctuation dynamos. We find that Landau damping on the electrons leads to a rapid decay of magnetic perturbations, impeding the dynamo. This collisionless damping process operates on spatial scales where electrons are nonmagnetized, reducing the range of scales where the magnetic field grows in high magnetic Prandtl number fluctuation dynamos. When electrons are not magnetized down to the resistive scale, the magnetic energy spectrum is expected to be limited by the scale corresponding to magnetic Landau damping or, if smaller, the electron gyroradius scale, instead of the resistive scale. In simulations we thus observe decaying magnetic fields where resistive MHD would predict a dynamo.

Författare

Istvan Pusztai

Chalmers, Fysik, Subatomär, högenergi- och plasmafysik

J. Juno

University of Maryland

A. Brandenburg

Kungliga Tekniska Högskolan (KTH)

J. M. TenBarge

Princeton University

Princeton Plasma Physics Laboratory

A. Hakim

Princeton Plasma Physics Laboratory

Manaure Francisquez

Massachusetts Institute of Technology (MIT)

Andréas Sundström

Chalmers, Fysik, Subatomär, högenergi- och plasmafysik

Physical Review Letters

0031-9007 (ISSN) 1079-7114 (eISSN)

Vol. 124 25 255102

Ämneskategorier

Astronomi, astrofysik och kosmologi

Annan fysik

Fusion, plasma och rymdfysik

DOI

10.1103/PhysRevLett.124.255102

PubMed

32639756

Mer information

Senast uppdaterat

2020-09-17