Prague Relativistic Astrophysics

Claudio Cremaschini

In this talk I will present an overview of the work done during my PhD, which concerns the theoretical foundations of kinetic theory for astrophysical plasmas that can be found in accretion discs around compact objects and in relativistic jets.

First, I will discuss the formulation of kinetic theory for non-relativistic accretion disc plasmas, with particular reference to collisionless axisymmetric magnetized and gravitationally-bound plasmas. I will show how exact quasi-stationary kinetic solutions (equilibria) of the Vlasov equation can be constructed which permit the treatment of quasi-stationary plasmas characterized by non-uniform fluid fields, including temperature and pressure anisotropies, azimuthal and poloidal flows and differential rotation. The significance of these solutions and the implications concerning the self-generation of stationary magnetic fields (kinetic dynamo) in accretion discs will be pointed out.

Second, I will present a solution of the so-called electromagnetic (EM) radiation-reaction (RR) problem characterizing the dynamics of finite-size classical relativistic charged particles. The derivation is based on a variational formulation of the EM RR effect. I will show that, from the Hamiltonian representation of the non-local EM RR effect, a canonical formulation of the kinetic theory for relativistic collisionless plasmas subject to RR can be obtained. This also permits the derivation of the corresponding relativistic fluid equations in which the non-local EM RR contribution can be proved to act as a non-conservative collisional operator. The physical properties of the solution and its astrophysical applications will be discussed.