Reconnecting Magnetic Flux Tubes as a Source of In Situ Acceleration in Extragalactic Radio Sources
Reconnecting Magnetic Flux Tubes as a Source of In Situ Acceleration in Extragalactic Radio Sources
复制标题
重新连接磁通量管作为河外射电源中的原位加速源
DOI：
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发表时间：
1995
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影响因子：
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通讯作者：
E. Blackman
中科院分区：
文献类型：
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作者：
E. Blackman
许多延伸的河外射电源需要一个电子的局部原位加速机制，部分原因是同步加速器的寿命短于整个发射区的整体旅行时间。如果这些源中的磁场局限在通量管中，则在等离子体β（粒子与磁压力之比）<$1的区域之间可能发生重联，即使在等离子体体积上平均的β可能是<$1。低β区的重联最有利于重联激波的加速。重联X点区域可以为随后的非热冲击加速提供注入电子，使其分布与观察到的光谱相当一致。因此，磁通管重联可能能够提供大规模喷流和波瓣所需的原位加速。
Many extended extragalactic radio sources require a local in situ acceleration mechanism for electrons, in part because the synchrotron lifetimes are shorter than the bulk travel time across the emitting regions. If the magnetic field in these sources is localized in flux tubes, reconnection may occur between regions of plasma β (ratio of particle to magnetic pressure) ≪1, even though β averaged over the plasma volume may be ≳1. Reconnection in low-β regions is most favorable to acceleration from reconnection shocks. The reconnection X-point regions may provide the injection electrons for their subsequent nonthermal shock acceleration to distributions reasonably consistent with observed spectra. Flux-tube reconnection might therefore be able to provide in situ acceleration required by large-scale jets and lobes.