| Abstract |
In a thermally bistable medium, cold, dense gas is separated from warm,
rarefied gas by thin phase transition layers, or fronts, in which
heating, radiative cooling, thermal conduction, and convection of
material are balanced. We calculate the steady-state structure of such
fronts in the presence of magnetic fields, including the processes of
ion-neutral drift and ion-neutral frictional heating. We find that
ambipolar diffusion efficiently transports the magnetic field across the
fronts, leading to a flat magnetic field strength profile. The thermal
profiles of such fronts are not significantly different from those of
unmagnetized fronts. The near uniformity of the magnetic field strength
across a front is consistent with the flat field strength-gas density
relation that is observed in diffuse interstellar gas. |