Photoionization of the hydrogen atom in strong magnetic fields of White Dwarfs

The photoionization cross-sections of the hydrogen atom in strong magnetic fields of magnetic White Dwarf stars were calculated with a direct numerical integration method using the Landau basis as a high field approach. The validity regime of these solutions overlap with those of the spherical symmetry and complement other recently developed methods. An important result is the relation between the density of states and the normalization for the more than one open channel regime leading to additional coupling terms not taken into account by multi channel quantum defect methods. Received: 16 March 1998 / Revised and Accepted: 14 July 1998