We study the acceleration of nonthermal ions and electrons due to the injection of turbulent wave energy which may occur in the accretion disk around compact objects. This scenario is relevant both to models of active galactic nuclei and cosmological models of gamma-ray bursts. We calculate stochastic and shock acceleration energy-gain time scales and radiation energy-loss time scales for electrons and ions. Depending on the parameters of the system, we find that the stochastic acceleration time scale for resonant electron/Whistler wave interactions can be ~ 10-1000 times faster than that of resonant ion/Alfven wave interactions. An implicit, finite-differencing numerical code has been developed to treat a set of coupled kinetic equations of waves, particles and photons. Particle phase density distribution f(p,mu ,t) evolves according to the Fokker-Planck equation (assuming spatial homogeneity); and the differential-integral equation is used to describe the evolution of photon occupation number density at different energies. For particles, the energy-gain and diffusive escape timescales are derived from the wave-particle resonant interactions by the dissipation of the magnetic turbulence, which is ~ 10% of the total magnetic field energy density and is assumed to be a power-law wave spectrum. Various radiation energy-loss processes are considered for protons and electrons, respectively. Pair processes are also included. By adopting different parameters, we attempt to use the code to model the spectra of the galactic black hole candidates (or Seyferts). This approach is different from the previous models where particle distributions were always assumed to be thermal (Maxwellian). Sucessful fitting will not only constrain the parameters used, also provide some insight to the hard-tail above MeV of Cygnus X-1 observed by Comptel.
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1994