RF capacitive discharges enhanced by an external magnetic field were investigated in air, pure methane and methane/argon mixture. The discharge operating parameters were varied in the ranges: frequency 13.56 MHz, pressure 0.1 - 10 Pa, dissipated power 70 - 80 W, magnetic
field induction 0 - 200 G. Nitrogen molecules in air plasma and CH radicals in methane and methane/argon plasma were studied by molecular emission spectroscopy methods. Rotational and vibrational temperatures of these molecules and radicals were estimated as a functions of the discharge parameters. In addition, the gas temperature were measured using a thermocouple.