Atomic Nitrogen Density Measurements in a Nanosecond Capillary Discharge

Abstract

This paper forms part of a larger study geared towards examining the atomic nitrogen production as a function of reduced electric fields, particularly in nanosecond type discharges. In this study, the atomic nitrogen density in a pure molecular nitrogen capillary discharge at 27 mbar is measured using two-photon absorption laser induced fluorescence (TALIF). Due to its small volume, the capillary provides an ideal geometry for achieving high levels of specific deposited energy into the plasma (> 1 eV per molecule) as well as high peak reduced electric fields (> 500 Td). Under these conditions, our results show that unusually high densities of atomic nitrogen are recorded, with the time evolution measurements indicating a peak dissociation fraction of slightly more than 10%. Further validation of these results with numerical simulations are ongoing, but on the current basis, support the notion that the capillary discharge is an extremely efficient configuration for the generation of nitrogen atoms.