TEST-PARTICLE MOTION IN A CLASSICAL RELATIVISTIC PLASMA

Starting from the covariant relativistic Balescu-Lenard (or Klinontovi ch-Silin) equation we derive a classical relativistic Fokker-Plank equ ation for a test-particle in a stable isotropic plasma with collective effects. The geometrical form of the diffusion tensor and friction 4- vector is given, and their behaviour is analyzed for various dynamical conditions: non relativistic and ultrarelativistic plasma. A H-theore m is proven. The main feature of the collective effects is that longit udinal oscillations of plasma appear, whereas transversal ones (Cerenk ov effect) do not. A limit value of the critical velocity of the test- panicle from which the plasm oscillations appear is found.