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Theoretical Study of Time Dependent Radiative Transfer in Relativistic Astrophysical Plasmas

相对论性天体物理等离子体中随时间变化的辐射传输的理论研究

基本信息

批准号：
61540175
负责人：
TAKAHARA Fumio
金额：
$ 1.15万
依托单位：
Tokyo Metropolitan University (1988)The University of Tokyo (1986-1987)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1988
项目状态：
已结题

项目摘要

I investigated the properties of relativistic plasmas which are produced near massive black holes in quasars and active galactic nuclei. I developed the numerical code which treats time dependent radiative transfer with Compton scattering and electron-positron pair production. I studied the time development of the instantaneously heated plasmas and found that the initial thermal energy of protons is transferred to electrons and photons on the time scale of about 10 times the initial Thomson time and about 20 percent of it is used for pair production. I also studied the stationary structure of plasma clouds and obtained the spatial distribution of proton and electron temperatures, pair concentration and photon spectra. In the central region the temperatures are lower and the pair concentration is higher than the uniform model predicts for the same heating rate. Pair atmosphere is less de veloped because of the anisotropic distribution of photons.The results are applied to the two-temperature accretion disks, taking account of the effects of electron-positron pairs. I found that stationary solutions are not realized for high accretion rates because pair equilibrium is not established for the expected range of electron temperature and Thomson depth. The critical accretion rate corresponds to only a few percent of the Eddington luminosity when either bremsstrahlung or the Comptonization of cyclotron higher harmonics dominates the radiation process.This result raises the problem of the behavior of the two-temperature accretion disks for high accretion rates. I examined one possibility of hydrodynamical wind blowing from hot disks in a simplified way and dound that a significant matter can be lost through the wind. A fuller investigation will be continued.

我研究了类星体和活动星系核中大质量黑洞附近产生的相对论等离子体的性质。我开发了用康普顿散射和电子-正电子对产生来处理随时间变化的辐射传输的数值程序。我研究了瞬时加热的等离子体的时间发展，发现质子的初始热能在大约10倍于初始汤姆森时间的时间尺度上转移到电子和光子，其中约20%用于对的产生。我还研究了等离子体云的静止结构，得到了质子和电子温度、对浓度和光子光谱的空间分布。在中心区域，对于相同的升温速率，温度较低，对浓度较高。由于光子的各向异性分布，对大气不发达。结果适用于双温度吸积盘，考虑了电子-正电子对的影响。我发现在高吸积率下不能实现稳定解，因为电子温度和汤姆森深度的预期范围内没有建立对平衡。当韧致辐射或回旋高次谐波的康普顿化控制辐射过程时，临界吸积率仅相当于爱丁顿光度的几个百分点。这一结果提出了高吸积率下双温度吸积盘的行为问题。我以一种简化的方式研究了从热盘吹来的流体动力风的一种可能性，并发现重要的物质可能会通过风失去。更全面的调查将继续进行。