Kinetics of excited species at high specific energy deposition: quenching by electrons in the afterglow of a nanosecond capillary discharge

摘要

Emission of the second positive system of molecular nitrogen, N_2(C~3Π_u) → N_2(B~3Π_g), in nanosecond pulsed discharge in nitrogen was studied. It was shown that observed emission decay is fast comparing to known from the literature values and that the emission decay is a function of specific deposited energy at fixed gas pressure. The density of electrons was measured in the discharge and in the near afterglow, tens-hundreds nanosecond after the discharge, and compared with calculated on the basis of measured electric current. It was concluded that active electron production takes place in the afterglow due to associative ionization from nitrogen metastable molecules, and that the observed fast quenching is caused by collisions with electrons.