Stochastic Particle Acceleration near Accreting Black Holes
Stochastic Particle Acceleration near Accreting Black Holes
复制标题
DOI：
10.1086/176631
复制
发表时间：
1995-08
期刊：
影响因子：
--
通讯作者：
C. Dermer;James A. Miller;Hui Li
中科院分区：
文献类型：
--
作者：
C. Dermer;James A. Miller;Hui Li
我们考虑黑洞磁层中粒子与等离子体波共振相互作用的随机加速。我们计算加速率和逃逸时间尺度的质子和电子共振与阿尔夫文波，和电子共振与哨声。假设Kolmogorov或Kraichnan波谱，在爱丁顿极限吸积，磁场强度接近均分，和湍流能量密度为总磁场能量密度的10%，我们发现阿尔夫文波加速质子到洛伦兹因子10^4$-10^6 $，然后才逃离系统。快模和哨声波对电子的加速可以产生相对论性电子的非热布居，其最大能量由与辐射损耗的竞争决定。由于主要的库仑损失，在较低的吸积率、磁场强度或湍流水平下，粒子的吸积和流出是不可能的。吸积光度相对于爱丁顿光度的增加可以触发热背景下的粒子加速，这种机制可以解释射电安静和射电大声活动星系核之间的差异。银河系X射线新星和耀变体伽马射线耀斑的瞬态X射线事件后流出的无线电发射成分的观测结果与这种情况雅阁。
We consider the stochastic acceleration of particles which results from resonant interactions with plasma waves in black hole magnetospheres. We calculate acceleration rates and escape time scales for protons and electrons resonating with Alfv\'en waves, and for electrons resonating with whistlers. Assuming either a Kolmogorov or Kraichnan wave spectrum, accretion at the Eddington limit, magnetic field strengths near equipartition, and turbulence energy densities $\sim 10\%$ of the total magnetic field energy density, we find that Alfv\'en waves accelerate protons to Lorentz factors $\lte 10^4$--$10^6$ before they escape from the system. Acceleration of electrons by fast mode and whistler waves can produce a nonthermal population of relativistic electons whose maximum energy is determined by a competition with radiation losses. Particle energization and outflow is not possible at lower accretion rates, magnetic field strengths, or turbulence levels due to dominant Coulomb losses. Increases in the accretion luminosity relative to the Eddington luminosity can trigger particle acceleration out of the thermal background, and this mechanism could account for the differences between radio-quiet and radio-loud active galactic nuclei. Observations of outflowing radio-emitting components following transient X-ray events in galactic X-ray novae and gamma-ray flares in blazars are in accord with this scenario.