Electron-to-proton temperature ratio T_e/T_p as a function of plasma β varying the R_low and R_high (definition given below in Eq. (13)). The vertical dashed black line marks the transition between the jet sheath region (β <  1) and the disk region (β >  1 ). The solid lines correspond to models with R_low = 1, and dotted lines show models with R_low = 0.1. The different colours indicate different R_high values.