Particle Accelerator in Pulsar Magnetospheres: Super-Goldreich-Julian Current with Ion Emission from the Neutron Star Surface
Particle Accelerator in Pulsar Magnetospheres: Super-Goldreich-Julian Current with Ion Emission from the Neutron Star Surface
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DOI：
10.1086/508317
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发表时间：
2006-08
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影响因子：
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通讯作者：
K. Hirotani
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文献类型：
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作者：
K. Hirotani
我们研究了二维极向平面上Crab脉冲星磁层中粒子加速器的自洽电动力学结构，求解了静电势的泊松方程以及电子、正电子和γ射线的玻尔兹曼方程。如果带隙的跨场厚度很薄，产生的电流密度将变为亚戈尔德雷希-朱利安解，给出了传统的外带隙解，但具有可以忽略的γ-射线光度。随着厚度的增加，产生的电流增加成为超Goldreich-Julian，给出了一种新的间隙解，其内部的加速电场基本上被屏蔽。在这种情况下，缝隙向具有小幅度正加速场的中子星延伸，以空间电荷限制流的形式从恒星表面提取离子。加速场在外层磁层高度未被屏蔽，导致了与观测结果一致的γ-射线谱形状。
We investigate the self-consistent electrodynamic structure of a particle accelerator in the Crab pulsar magnetosphere on the two-dimensional poloidal plane, solving the Poisson equation for the electrostatic potential together with the Boltzmann equations for electrons, positrons, and γ-rays. If the transfield thickness of the gap is thin, the created current density becomes sub-Goldreich-Julian, giving the traditional outer-gap solution but with negligible γ-ray luminosity. As the thickness increases, the created current increases to become super-Goldreich-Julian, giving a new gap solution with substantially screened acceleration electric field in the inner part. In this case, the gap extends toward the neutron star with a small-amplitude positive acceleration field, extracting ions from the stellar surface as a space-charge-limited flow. The acceleration field is highly unscreened in the outer magnetosphere, resulting in a γ-ray spectral shape that is consistent with the observations.