Top panels: FWHM of the broad Balmer line as a function of the CR acceleration efficiency for a neutral fraction h_N = 10% (left) and h_N = 50% (right). Different lines show a different electron-ion equilibration level as labeled. The shaded area shows the FWHM as measured in the SE_out region by Helder et al. (2013) at 1σ level. Bottom panels: electron temperature immediately behind the shock as a function of the CR acceleration efficiency for h_N = 10% (left) and h_N = 50% (right). The shaded area shows T_e as measured by Helder et al. (2011), while the straight line at ~0.05 keV is the value estimated by the same authors for T_e immediately behind the shock. All results refer to a shock velocity of V_sh = 1531     km   s^-1 and a total gas density of n₀ = 1   cm^-3.