Compton Scattering in Ultrastrong Magnetic Fields: Numerical and Analytical Behavior in the Relativistic Regime
Compton Scattering in Ultrastrong Magnetic Fields: Numerical and Analytical Behavior in the Relativistic Regime
复制标题
超强磁场中的康普顿散射：相对论体系中的数值和分析行为
DOI：
10.1086/309357
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
C. Mercer
中科院分区：
文献类型：
--
作者：
P. Gonthier;A. Harding;M. Baring;Rachel M. Costello;C. Mercer
本文探讨了强磁场对相对论性电子康普顿散射的影响。最近关于相对论性电子的上散射和能量损失的研究，使用非相对论性、磁汤姆逊散射或克莱因-西西那散射的非共振截面，并没有考虑强场（>4 × 1012 G）的相对论性量子效应。对于广义相对论电子沿磁场运动的情况，我们导出了精确QED散射截面的简化表达式。为了便于天体物理模型的应用，我们还开发了微分和总偏振相关截面的紧凑近似表达式，后者很好地表示了即使在软伽马中继器和异常x射线脉冲星的恒星表面附近环境中存在的高场中也能准确地表示总QED截面。我们发现强磁场显著降低了康普顿散射截面，当入射光子能量超过电子静止系中的mec2时，在共振处。横截面强烈依赖于最终散射光子的偏振。在回旋加速器基元以下，大多数垂直偏振的光子以散射的形式产生，这种情况也出现在亚临界场的共振之上。然而，一个有趣的发现是，对于超临界场，平行偏振光子的优势是由回旋加速器基本面的散射产生的。这种特性既是相对论性的，也是磁效应，在汤姆逊极限或克莱因-西西那极限中是不存在的。
This paper explores the effects of strong magnetic fields on the Compton scattering of relativistic electrons. Recent studies of upscattering and energy loss by relativistic electrons that have used the nonrelativistic, magnetic Thomson cross section for resonant scattering or the Klein-Nishina cross section for nonresonant scattering do not account for the relativistic quantum effects of strong fields (>4 × 1012 G). We have derived a simplified expression for the exact QED scattering cross section for the broadly applicable case in which relativistic electrons move along the magnetic field. To facilitate applications to astrophysical models, we have also developed compact approximate expressions for both the differential and total polarization-dependent cross sections, with the latter representing well the exact total QED cross section even at the high fields believed to be present in environments near the stellar surfaces of soft gamma repeaters and anomalous X-ray pulsars. We find that strong magnetic fields significantly lower the Compton scattering cross section below and at the resonance when the incident photon energy exceeds mec2 in the electron rest frame. The cross section is strongly dependent on the polarization of the final scattered photon. Below the cyclotron fundamental, mostly photons of perpendicular polarization are produced in scatterings, a situation that also arises above this resonance for subcritical fields. However, an interesting discovery is that for supercritical fields, a preponderance of photons of parallel polarization results from scatterings above the cyclotron fundamental. This characteristic is both a relativistic and a magnetic effect not present in the Thomson or Klein-Nishina limits.