Numerical simulations of radiative processes in magnetized compact sources such as hot accretion disks around black holes, relativistic jets in active galaxies and gamma-ray bursts are complicated because the particle and photon distributions span many orders of magnitude in energy, they also strongly depend on each other, the radiative processes behave significantly differently depending on the energy regime, and finally due to the enormous difference in the time-scales of the processes. We have developed a novel computer code for the time-dependent simulations that overcomes these problems. The processes taken into account are Compton scattering, electron-positron pair production and annihilation, Coulomb scattering as well as synchrotron emission and absorption. No approximation has been made on the corresponding rates. For the first time, we solve coupled integro-differential kinetic equations for photons and electrons/positrons without any limitations on the photon and lepton energies. A numerical scheme is proposed to guarantee energy conservation when dealing with synchrotron processes in electron and photon equations. We apply the code to model non-thermal pair cascades in the blackbody radiation field, to study the synchrotron self-absorption as particle thermalization mechanism, and to simulate time evolution of stochastically heated pairs and corresponding synchrotron self-Compton photon spectra which might be responsible for the prompt emission of gamma-ray bursts. Good agreement with previous works is found in the parameter regimes where comparison is feasible, with the differences attributable to our improved treatment of the microphysics.
The Anisotropic Transfer of Resonance Photons in Hot Plasmas on Magnetized White Dwarfs
为了证实Terada等人（2001）提出的磁激变变星中热吸积柱中共振光子对白矮星的各向异性效应，用ASCA方法对7个极和12个中间极进行了系统的研究.类He Fe K $_α$线的等效极线宽度在其自旋周期上被系统地调制，在极接通阶段，其宽度增加。这意味着各向异性机制通常在极性之间起作用。另一方面，中间极性的那些在统计上与未调制一致，上限为1.5倍调制。这可能是由于不同的吸积方式，如极光幕（Rosen et al 1988），使等离子体沿水平轴变得光学薄，也为共振线，或因为较大的康普顿散射的光学深度，如果发射区具有相同的硬币状形状的极性。
