A Plane-Parallel Wind Solution For Testing Numerical Simulations of   Photoevaporation
  Here we derive a Parker-wind like solution for a stratified, plane-parallel atmosphere undergoing photoionisation. The difference compared to the standard Parker solar wind is that the sonic point is crossed only at infinity. The simplicity of the analytic solution makes it a convenient test problem for numerical simulations of photoevaporation in protoplanetary discs. 
Mark A. Hutchison and Guillaume Laibe
astro-ph.SR