Magnetic insulation in nitrogen subjected to crossed fields

Abstract

In the E/N range from 150 to 400 Td (1 Td = 10-17 Vcm2), the combination of crossed magnetic fields resulting in avalanche growth inhibition in nitrogen are evaluated by means of a Monte Carlo simulation. The simulation technique employed analysis swarm development without any a priori assumptions on electron energy distribution functions and electron collisional frequencies. For the combined crossed fields evaluated, variation of number of free electrons, average positions of the swarm and pulsed Townsend energies with respect to sampling times are reported. The pulsed Townsend energies indicate considerable reduction in the mean energies when the electron avalanche at a given E/N is inhibited upon the application of a specific magnetic field value. Effectively reduced electric fields are calculated from the magnetic deflection angles obtained from the simulation. It is observed that the calculated effectively reduced fields with the related pulsed Townsend mean energies favor the effectively reduced field concept in the combined fields.

Electron Swarm Parameters in Methane-Nitrogen Mixtures

“…The drift velocity is increasing as the reduced electrical field increases. The calculated results are compatible with the measured [30] and Monte Carlo results [10,31]. The reduced effective ionization coefficient in pure nitrogen is shown in Fig.…”

“…4. Present result is compared with the Boltzmann solution [27] and with the Monte Carlo method solutions in the literature [10,12,28,29]. The electron mean energy increases as the reduced electric field increases.…”

“…Nitrogen is one of the important alternatives for the use of greenhouse gases in the gaseous electronics and plasma processing industry due to its inherent advantages, such as sufficient level of insulation strength, nonflammability, non-toxic, and less cost [9,10]. The application of N 2 based plasma and gas-insulated equipment * corresponding author; e-mail: stezcan@gazi.edu.tr technologies can be found in high voltage devices, diffuse discharge switches, exhaust gas pollution control, plasma etching, decontamination and surface treatment industries [11,12].…”

Suppression of Electron Avalanches in Ultra-Dilute SF6-N2 Mixtures Subjected to Time-Invariant Crossed Fields

“…At an E/N value of 400 Td, the B/N resulting in avalanche inhibition in nitrogen is 2.56 × 10 −18 Tcm 3 [33]. However, in the present paper, the required B/N for avalanche inhibition is reduced to 2.17 × 10 −18 Tcm 3 at 0.50% SF 6 concentration and to 1.99 × 10 −18 Tcm 3 at 0.75% SF 6 content.…”

“…The authors' recent work discusses magnetic insulation in nitrogen [33]. The present paper investigates the response of an ultra-dilute SF 6 component in the binary mixture with the nitrogen gas acting as the buffer gas slowing down the electrons effectively under the crossed fields.…”