Rotation Temperature of Nitrogen DC Glow Discharge Obtained by Optical Emission spectroscopy

摘要

s: Measurements of rotational temperature as low as several hundred Kelvins have been achieved using optical emission spectroscopy (OES) in nitrogen direct current (DC) glow discharge. The strongest band of the first negative system of nitrogen was chosen to deduce the rotational temperature at 4 different positions in nitrogen DC glow discharge: the back of cathode; cathode sheath; positive column and anode glow. In positive column the rotational temperature increased apparently with the increasing discharge voltage from 500-1000V when the pressure was 10Pa. But with pressure of 20Pa the rotational temperature in positive column increased slightly with the increase of discharge voltage. On the contrary, the rotational temperature in cathode sheath took reverse tendencies when the discharge voltage varies from 500-1000V. As regard the anode glow, the rotational temperature at 10Pa decreased with the increase of discharge voltage, but that at 20Pa increased. We attribute the different tendencies of the rotational temperature to the different discharge statues at different pressures. When the discharge voltage varies from 500 to 1100V, the discharge with pressure of 10Pa is normal glow and that with 20Pa is abnormal glow.