本文研究了脉冲星极冠上方内加速区（IAR）火花放电系统的演化。极冠的表面被加热到大约$10^6$ K的温度，并由于从恒星表面发射的带正电的离子而形成部分屏蔽间隙（PSG）。由于可变的$E$ x $B$漂移，火花在其寿命期间滞后于共旋转速度。在PSG中，火花放电出现在表面温度低于离子从表面自由流动的临界水平（$T_i$）的位置。由于在这些较低温度区域中沿着磁场线发展的大的电势降而开始产生火花，并且随后回流颗粒将表面加热到$T_i$。温度调节要求极盖紧密地填充有火花，并且要求在其边界周围连续存在火花，因为闭合的场线区域不可能加热。我们估计了IAR中火花系统的时间演化，该系统显示了沿两个不同方向的火花形成的逐渐转变，类似于极冠两半中的顺时针和逆时针运动。由于火花模式在两个半部分中的差异移位，中心火花发展代表核心发射。模拟了非偶极极冠不同方向的火花过程的时间演化，再现了与亚脉冲漂移相关的各种观测特征。
英文摘要：
We have investigated the evolution of a system of sparking discharges in the inner acceleration region (IAR) above the pulsar polar cap. The surface of the polar cap is heated to temperatures around $10^6$ K and forms a partially screened gap (PSG) due to thermionic emission of positively charged ions from the stellar surface. The sparks lag behind the co-rotation speed during their lifetimes due to variable $E$x$B$ drift. In a PSG the sparking discharges arise in locations where the surface temperatures go below the critical level ($T_i$) for ions to freely flow from the surface. The sparking commences due to the large potential drop developing along the magnetic field lines in these lower temperature regions and subsequently the back streaming particles heat the surface to $T_i$. The temperature regulation requires the polar cap to be tightly filled with sparks and a continuous presence of sparks is required around its boundary since no heating is possible from the closed field line region. We have estimated the time evolution of the sparking system in the IAR which shows a gradual shift in the spark formation along two distinct directions resembling clockwise and anti-clockwise motion in two halves of the polar cap. Due to the differential shift of the sparking pattern in the two halves, a central spark develops representing the core emission. The temporal evolution of the sparking process was simulated for different orientations of the non-dipolar polar cap and reproduced the diverse observational features associated with subpulse drifting.
Axion Hair and Pulsar Electrodynamics: modelling, discharge dynamics, and particle-in-cell simulations
Rudolf Peierls Centre for Theoretical Physics, University of Oxford（牛津大学鲁道夫·派尔斯理论物理中心）；Deutsches Elektronen-Synchrotron DESY（德国电子同步加速器中心）；II. Institute of Theoretical Physics, Universität Hamburg（汉堡大学第二理论物理研究所）；Department of Theoretical Physics, CERN（欧洲核子研究中心理论物理部）；Dipartimento di Fisica, “Sapienza” Università di Roma & Sezione INFN Roma1（罗马第一大学物理系及INFN罗马一分部）；Weizmann Institute of Science（魏茨曼科学研究所）；Institut de Física d’Altes Energies (IFAE) and Barcelona Institute of Science and Technology (BIST)（高等能源物理研究所及巴塞罗那科学与技术研究院）；Institute for Advanced Study, Princeton（普林斯顿高等研究院）；University of Maryland（马里兰大学）；Johns Hopkins University（约翰斯·霍普金斯大学）
Time-dependent pair cascades in magnetospheres of neutron stars I. Dynamics of the polar cap cascade with no particle supply from the neutron star surface
University of Potsdam（波茨坦大学）；Astronomical Institute of the Czech Academy of Sciences（捷克科学院天文研究所）；Max-Planck Institute for Radio Astronomy（马克斯·普朗克射电天文研究所）；Deutsches Elektronen-Synchrotron DESY（德国电子同步辐射中心）；Masaryk University（马萨里克大学）；University of Southampton（南安普顿大学）
