论文标题
辐射性相对论磁性水力动力学模拟，中子星形柱的笛卡尔几何形状
Radiative Relativistic Magnetohydrodynamic Simulations of Neutron Star Column Accretion in Cartesian Geometry
论文作者
论文摘要
高亮度积聚在强磁中子恒星上导致辐射压力占主导的磁性积聚柱。我们使用二维辐射相对论的磁性水力动力学模拟研究了这些柱的动力学，将考虑率的考虑限制为适度的积聚速率，在这种情况下，该柱的高度足够低，以至于可以采用笛卡尔几何形状。通过$ \ simeq 10-25 $ 〜KHz的积聚冲击的高频振荡，通过高频振荡动态维护柱结构。这些振荡之所以出现，是因为有必要通过散装垂直运动重新分布在积聚冲击下释放的功率，以平衡冷却并提供垂直压力支撑，以防止重力。侧向冷却总是主导着内部能量的损失。除了垂直振荡外，我们的模拟中还形成了光子气泡，并为色谱柱结构增加了其他空间复杂性。它们本身并不是对振荡的负责，并且似乎不会影响振荡时期。但是，它们增强了辐射的垂直运输，并增加了发光度的振荡幅度。我们模拟中的时间平均柱结构类似于标准1D固定模型中的趋势，主要区别在于，由于2D柱形状的冷却效率较高，冲击锋的时间平均高度较低。
High luminosity accretion onto a strongly magnetized neutron star results in a radiation pressure dominated, magnetically confined accretion column. We investigate the dynamics of these columns using two-dimensional radiative relativistic magnetohydrodynamic simulations, restricting consideration to modest accretion rates where the height of the column is low enough that Cartesian geometry can be employed. The column structure is dynamically maintained through high-frequency oscillations of the accretion shock at $\simeq 10-25$~kHz. These oscillations arise because it is necessary to redistribute the power released at the accretion shock through bulk vertical motions, both to balance the cooling and to provide vertical pressure support against gravity. Sideways cooling always dominates the loss of internal energy. In addition to the vertical oscillations, photon bubbles form in our simulations and add additional spatial complexity to the column structure. They are not themselves responsible for the oscillations, and they do not appear to affect the oscillation period. However, they enhance the vertical transport of radiation and increase the oscillation amplitude in luminosity. The time-averaged column structure in our simulations resembles the trends in standard 1D stationary models, the main difference being that the time-averaged height of the shock front is lower because of the higher cooling efficiency of the 2D column shape.
