Distribution of the ionization parameter, ξ, over the Be decretion disk for our γ Cas default model (Table 1). The hard X-ray source is located to the right at x = 375 R_⊙, y = 0. The labels on the different contours correspond to the value of log ξ (from –4.0 for the blue-violet contour to –6.5 for the red contour). The hatched area lies in the shadow of the Be star and is thus not illuminated by the hard X-ray source.