论文标题
重复快速无线电爆发中磁层曲率辐射的极化
Polarisation of magnetospheric curvature radiation in repeating fast radio bursts
论文作者
论文摘要
快速的无线电胸围（FRB）可以表现出各种各样的极化属性，不仅在来源之间，而且从爆发到爆发。在这项工作中，我们从高度磁化的中子星的磁层中的大部分带电束中重新审视了相干曲率辐射的极化特征。已经观察到FRB具有多种极化特征，例如高水平的圆极化或圆形极化的符号变化。当视线位于发射光束内部（梁几何形状）时，将会出现高线性极化，而在外部（偏离梁几何形状）时，将存在高圆极化。通过考虑``散装形状''的两种情况（厚与薄），我们将模型应用模型来解释三个重复的FRB的极化特征（FRB 20201124A，FRB 20190520B和FRB 20121102a）。大多数爆发都以线性极化为主，而可忽略的事件在圆极化中具有符号变化，这表明这种FRB最有可能是由``薄''散装块发出的，具有较大的开口角。 ``薄''的大容量的较高概率对于理解重复的FRB中央发动机（即火花动力学）在中子星表面上产生不同大部分的能量束。
Fast radio busts (FRBs) can exhibit a wide variety of polarisation properties, not only between sources but also from burst to burst for a same one. In this work, we revisit the polarisation characters of coherent curvature radiation from a bulk of charged bunches in the magnetosphere of a highly magnetized neutron star. FRBs have been observed to have a variety of polarisation features, such as high levels of circular polarisation or a sign change of circular polarisation. High linear polarisation would appear when the line of sight is inside the emission beam (the on-beam geometry), whereas high circular polarisation would be present when it is outside (the off-beam geometry). By considering two scenarios of the ``bulk shapes'' (thick vs. thin), we apply the model to explain the polarisation features of three repeating FRBs (FRB 20201124A, FRB 20190520B and FRB 20121102A). Most bursts are dominated by linear polarisation and negligible events have sign changes in circular polarisation, suggesting that such FRBs are most likely to be emitted by the ``thin'' bulks with large opening angles. The higher probability of ``thin'' bulks could be meaningful for understanding repeating FRB central engine, i.e., the sparking dynamics to produce different bulks of energetic bunches on a neutron star surface.
