Charged Particle Transport in Gaseous Nitrogen at Intermediate E/N using the Voltage Transient Method

Abstract

A pulsed swarm of charged particles crossing an inter-electrode gap under the influence of an applied electric field E will produce a pulsed current in the external circuit which, when integrated over time, will result in a transient voltage pulse, the shape and magnitude of which is characteristic of the number and type of charged particles. This voltage transient technique has been used to investigate a gas discharge in nitrogen gas at values of EIN (the ratio of applied electric field to gas number density), such that ionisation is non-negligible. The voltage transients have been subjected to a theoretical analysis, which has previously been reported, which includes not only cathode and anode image terms but also both electron and ion diffusion terms. Electron transport parameters are reported for EIN ::; 350 Td (1 Td = 10-17 V cm2). Data are also obtained for the drift velocities and diffusion coefficients of the ions operative within the nitrogen discharge. An estimate is obtained for the collisional decay rate of Nt.