Conversion of relativistic pair energy into radiation in the jets of active galactic nuclei
Conversion of relativistic pair energy into radiation in the jets of active galactic nuclei
复制标题
将相对论对能量转换为活动星系核喷流中的辐射
DOI：
10.1051/0004-6361:20020975
复制
发表时间：
2002
影响因子：
6.5
通讯作者：
C. Schuster
中科院分区：
文献类型：
--
作者：
R. Schlickeiser;R. Vainio;M. Boettcher;I. Lerche;M. Pohl;C. Schuster
活动星系核（AGN）的非热辐射是由相对论喷流驱动的。这些喷流的组成-轻子喷流还是强子喷流-仍在争论中。我们研究了准直相对论对外流中动能通过与周围星际介质相互作用转化为辐射的微物理细节。从与电子对流出同步运动的坐标系看，星际质子和电子代表在电子对等离子体中以相对论速度传播的质子-电子束。我们表明，该光束激发静电和低频磁流体Alfvin型波通过双流不稳定性对背景等离子体，我们计算的时间演化的光束粒子的分布函数和产生的等离子体波湍流功率谱。对于标准活动星系核喷流和环境参数，我们表明，星际质子和电子的初始光束分布迅速放松到平台分布的平行动量，从而转移到所产生的静电湍流的电场波动的光束粒子的初始能量密度的一半。在相当长的时间尺度上，稳定的星际电子和质子将通过它们自身产生的横向湍流而各向同性，从而在流出对等离子体中被拾取。这些较长的时间尺度也是从平台电子和质子的横向磁流体湍流的发展的特征。这种上游和下游的水磁湍流对于扩散激波加速在与对流出相关的外部或内部激波下起作用是至关重要的。
It is generally accepted that relativistic jet outflows power the nonthermal emission from active galactic nu- clei (AGN). The composition of these jets - leptonic versus hadronic - is still under debate. We investigate the microphysical details of the conversion process of the kinetic energy in collimated relativistic pair outflows into radiation through interactions with the ambient interstellar medium. Viewed from the coordinate system comoving with the pair outflow, the interstellar pro- tons and electrons represent a proton-electron beam propagating with relativistic speed in the pair plasma. We demonstrate that the beam excites both electrostatic and low-frequency magnetohydrodynamic Alfven-type waves via a two-stream instability in the pair background plasma, and we calculate the time evolution of the distribution functions of the beam particles and the generated plasma wave turbulence power spectra. For standard AGN jet outflow and environment parameters we show that the initial beam distributions of interstellar protons and electrons quickly relax to plateau-distributions in parallel momentum, transferring thereby one-half of the initial energy density of the beam particles to electric field fluctuations of the generated electrostatic turbulence. On considerably longer time scales, the plateaued interstellar electrons and protons will isotropise by their self-generated transverse turbulence and thus be picked-up in the outflow pair plasma. These longer time scales are also characteristic for the development of transverse hydromagnetic turbulence from the plateaued electrons and protons. This hy- dromagnetic turbulence upstream and downstream is crucial for diusive shock acceleration to operate at external or internal shocks associated with pair outflows.