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Title: Kinetic axisymmetric gravitational equilibria in collisionless accretion disk plasmas

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.3455537· OSTI ID:21389128
;  [1];  [2]
  1. International School for Advanced Studies (SISSA) and INFN, Trieste 34136 (Italy)
  2. Department of Mathematics and Informatics, Trieste University, Trieste 34127 (Italy)

A theoretical treatment is presented of kinetic equilibria in accretion disks (AD) around compact objects, for cases where the plasma can be considered as collisionless. The plasma is assumed to be axisymmetric and to be acted on by gravitational and electromagnetic fields; in this paper, the particular case is considered where the magnetic field admits a family of toroidal magnetic surfaces, which are locally mutually nested and closed. It is pointed out that there exist asymptotic kinetic equilibria represented by generalized bi-Maxwellian distribution functions and characterized by primarily toroidal differential rotation and temperature anisotropy. It is conjectured that kinetic equilibria of this type can exist which are able to sustain both toroidal and poloidal electric current densities, the latter being produced via finite Larmor-radius effects associated with the temperature anisotropy. This leads to the possibility of existence of a new kinetic effect - referred to here as a 'kinetic dynamo effect - resulting in the self-generation of toroidal magnetic field even by a stationary plasma, without any net radial accretion flow being required. The conditions for these equilibria to occur, their basic theoretical features, and their physical properties are all discussed in detail.

OSTI ID:
21389128
Journal Information:
Physics of Plasmas, Vol. 17, Issue 7; Other Information: DOI: 10.1063/1.3455537; (c) 2010 American Institute of Physics; ISSN 1070-664X
Country of Publication:
United States
Language:
English