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arXiv 1209.4063astro-ph.HE
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磁星周围的电子-正电子流

Electron-positron flows around magnetars

Andrei M. Beloborodov

摘要:

磁星扭曲的磁层必须维持持续的电子-正电子电浆流。热中子星周围的辐射场控制着流体动力学。用虚光束法求解了自洽辐射场中等离子体的运动问题。等离子体和辐射通过共振散射交换动量,并自组织成具有明确定义的、递减的洛伦兹因子的“辐射锁定”流出。磁星周围有一个扩展区域,等离子体流是超相对论的;它的洛伦兹因子是自我调节的,因此它可以稍微散射热光子。在赤道外区,流动变得缓慢而不透明,减速的等离子体在那里聚集和湮灭;这个区域充当了中子星发射的热光子的反射器。e+流携带电流,其由适度的感应电场维持。电场与辐射场的意愿相反,保持电子和正电子速度之间的分离。双流不稳定性是不可避免的,诱导的湍流可以产生低频发射。特别是,射电辐射可能会围绕恒星的磁偶极轴逃逸。大部分的流动能量被转换成硬X射线发射,这在所附的论文中进行了研究。

英文摘要:

The twisted magnetospheres of magnetars must sustain a persistent flow of electron-positron plasma. The flow dynamics is controlled by the radiation field around the hot neutron star. The problem of plasma motion in the self-consistent radiation field is solved using the method of virtual beams. The plasma and radiation exchange momentum via resonant scattering and self-organize into the "radiatively locked" outflow with a well-defined, decreasing Lorentz factor. There is an extended zone around the magnetar where the plasma flow is ultra-relativistic; its Lorentz factor is self-regulated so that it can marginally scatter thermal photons. The flow becomes slow and opaque in an outer equatorial zone, where the decelerated plasma accumulates and annihilates; this region serves as a reflector for the thermal photons emitted by the neutron star. The e+- flow carries electric current, which is sustained by a moderate induced electric field. The electric field maintains a separation between the electron and positron velocities, against the will of the radiation field. The two-stream instability is then inevitable, and the induced turbulence can generate low-frequency emission. In particular, radio emission may escape around the magnetic dipole axis of the star. Most of the flow energy is converted to hard X-ray emission, which is examined in the accompanying paper.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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