毫秒脉冲星与白矮星磁层中的对放电及射电辐射
Pair Discharges and Radio Emission from Millisecond-Pulsar and White-Dwarf Magnetospheres
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中文总结 AI 辅助
该研究针对弱场致密天体磁层，提出含两类QED过程的新型对放电机制，通过粒子模拟验证其可产生对级联与相干射电辐射，解释了毫秒脉冲星和白矮星的射电活动。
中文摘要 AI 辅助
在具有相对弱磁场的致密天体（包括毫秒脉冲星和白矮星）中观测到了相干射电辐射，其中白矮星被认为是长周期射电暂现源的可能来源。在这类环境中，由曲率辐射和单光子对产生驱动的标准对放电机制可能失效，因为低磁场强度会抑制光子转换。我们分析了一种在弱场磁层中高效运行的放电机制，该机制包含两种顶点的量子电动力学过程：逆康普顿散射背景光子，随后根据种子光子温度产生双光子或单光子对。利用结合精确QED截面的第一性原理辐射粒子模拟，我们证明这些机制能在毫秒脉冲星磁层和热白矮星环境中可靠产生对级联。该系统呈现极限环行为，并产生能生成相干射电辐射的电磁场涨落，为弱场致密天体的射电活动提供了自然解释。
英文摘要
Coherent radio emission is observed from compact astrophysical objects with relatively weak magnetic fields, including millisecond pulsars and white dwarfs, the latter being proposed as possible sources of long-period radio transients. In such environments, the standard pair discharge mechanism---driven by curvature radiation and one-photon pair production---can fail because the low magnetic field strength suppresses photon conversion. We analyze a discharge mechanism that operates efficiently in weak-field magnetospheres, including two-vertex quantum electrodynamic processes: inverse Compton up-scattering of background photons followed by either two-photon or one-photon pair creation depending on the seed photon temperature. Using first-principles radiative particle-in-cell simulations incorporating exact QED cross sections, we demonstrate that these mechanisms robustly generate pair cascades in millisecond-pulsar magnetospheres and in hot white-dwarf environments. The resulting system exhibits limit-cycle behavior and generates electromagnetic field fluctuations capable of producing coherent radio emission, providing a natural explanation for radio activity in low-field compact objects.
