Transition from gas to plasma kinetic equilibria in gravitating axisymmetric structures
Abstract
The problem of the transition from gas to plasma in gravitating axisymmetric structures is addressed under the assumption of having initial and final states realized by kinetic Maxwellianlike equilibria. In astrophysics, the theory applies to accretiondisc scenarios around compact objects. A formulation based on nonrelativistic kinetic theory for collisionless systems is adopted. Equilibrium solutions for the kinetic distribution functions describing the initial neutral matter and the resulting plasma state are constructed in terms of singleparticle invariants and expressed by generalized Maxwellian distributions. The final plasma configuration is related to the initial gas distribution by the introduction of appropriate functional constraints. Qualitative aspects of the solution are investigated and physical properties of the system are pointed out. In particular, the admitted functional dependences of the fluid fields carried by the corresponding equilibrium distributions are determined. Then, the plasma is proved to violate the condition of quasineutrality, implying a net charge separation between ions and electrons. This result is shown to be independent of the precise realization of the plasma distribution function, while a physical mechanism able to support a nonneutral equilibrium state is proposed.
 Publication:

Physics of Plasmas
 Pub Date:
 April 2014
 DOI:
 10.1063/1.4871494
 Bibcode:
 2014PhPl...21d2902C