We report calculations of photoionization cross sections for hydrogen atoms in white-dwarf magnetic fields. The calculations were implemented using the adiabatic-basis-expansion method and the coupled-channel theory, which are valid for low and high magnetic fields, respectively. The magnetic fields span over a typical white-dwarf strength regime from 23.5 to 2350 MG. Lyman and Balmer continuum spectra for bound–free transitions in magnetic white-dwarf stars are presented with various field strengths. The current results are compared with those from the complex-rotation method. Excellent agreement is shown in the energy region away from Landau thresholds, but the pronounced discrepancies are found in the small vicinity below Landau thresholds. The agreement shown illustrates the reliability of these two theoretical approaches used, while the discrepancies should be attributed to the limitation of the complex-rotation method. The photoionization cross sections presented here should be applicable to the analyses of continuum spectra and their polarization properties observed in the atmospheres of hydrogen-dominated magnetic white dwarfs.

我们报告了白矮星磁场中氢原子的光电离截面的计算。计算是使用绝热基膨胀法和耦合通道理论实现的，它们分别适用于低磁场和高磁场。磁场跨越典型的白矮星强度范围，从 23.5 到 2350 MG。磁性白矮星中自由跃迁的莱曼和巴尔默连续谱以不同的场强呈现。将当前结果与复数旋转方法的结果进行比较。在远离 Landau 阈值的能量区域中显示出极好的一致性，但在低于 Landau 阈值的小范围内发现了明显的差异。所示的一致性说明了所使用的这两种理论方法的可靠性，而差异应该归因于复杂旋转方法的局限性。这里介绍的光电离截面应该适用于在氢主导的磁性白矮星的大气中观察到的连续谱及其极化特性的分析。