Motional Stark effect on bound-free spectra

Abstract

The motion of atoms through a magnetic field (due to a change in reference frame) will result in an additional electric field felt by the electrons in that atom. The motional Stark effect is a well-established effect that has been approximately included in calculations of spectra of magnetized plasmas, usually through diagonalizing the Hamiltonian. The motional Stark effect for continuum states is poorly defined due to an overlap integral that results in a Dirac delta function. This paper presents a workaround by evaluating the motional Stark effect in the Green's function within the scattering formalism. We report on some results pertaining to bound-free spectra for white dwarf and neutron star magnetic field strengths. In most cases, resonances in the continuum are shifted and broadened. This behavior has the effect of raising the Rosseland mean opacity in white dwarfs and neutron star atmospheres.