Temporally resolved measurements of gas temperature using optical emission spectroscopy enhanced with probing nanosecond plasma pulse

摘要

In this work, a novel method for gas temperature measurements with 5 ns temporal resolution is proposed and further applied to determine the gas temperature in the wake of Nanosecond Repetitive Pulsed (NRP) discharge at room temperature/pressure. The method is based on the classical rotational/vibrational temperature measurements from optical emission spectroscopy (OES) of the N2 2nd positive system used in conjunction with probing nanosecond plasma pulse. The probing pulse is used in order to excite the emission of the 2nd positive system at the desired moment of time. The spectra is acquired during first 5 ns after the probing pulse initiation in order to eliminate any gas heating due to the probing pulse, and, finally, rotational temperature and bulk gas temperature are determined. The gas temperature in the wake of the NRP discharge was measured using this method and it decreased from about 2600 K at 20 us after the NRP discharge initiation to 650 K at 500 us.