2010/01/31 by Claudio Cremaschini, John C. Miller, Massimo Tessarotto · 20 citations
Earth and Planetary Sciences · Physics and Astronomy · #Accretion (finance) #Anisotropy #Astrophysics #Astrophysics and Star Formation Studies #Atomic and Molecular Physics #Classical mechanics #Differential rotation #Dynamo #Dynamo theory #Gravitation #Gyrokinetics #Gyroradius #High-pressure geophysics and materials #Kinetic energy #Magnetic field #Magnetohydrodynamics #Mechanics #Physics #Plasma #Quantum mechanics #Rotational symmetry #Tokamak #Toroid #Toroidal and poloidal #Vlasov equation #astro-ph.HE #physics.plasm-ph
paper · pdf · doi:10.1063/1.3455537
published in Physics of Plasmas 17(7), 072902 (American Institute of Physics) · 13 pages, 1 figure Accepted for publication in Physics of Plasmas
arxiv created 2010/06/07 · openalex publication_date 2010/07/01 · arxiv updated 2015/05/18 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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.