Derivation and test of high order fluid model for streamer discharges

A high order fluid model for streamer dynamics is developed by closing the system after the 4th moment of the Boltzmann equation in local mean energy approximation. This is done by approximating the high order pressure tensor in the heat flux equation through the previous moments. Mathematical characteristics of the system is studied. Then planar ionization fronts for negative streamers in Nsub2 are simulated with the classical streamer model, MC-PIC particle model, and with the present higher order model

High order fluid model for streamer discharges

A high order fluid model for streamer discharges is developed and used to investigate propagation of negative streamer fronts in N2 . Mo- mentum transfer theory is employed to evaluate the collision terms and close the system of moment/balance equations. The results of simulations are compared with those obtained by a PIC/MC method and by the classical first order fluid model based on the drif

Comparing plasma fluid models of different order for 1D streamer ionization fronts

We evaluate the performance of three plasma fluid models: the first order reaction-drift-diffusion model based on the local field approximation; the second order reaction-drift-diffusion model based on the local energy approximation and a recently developed high order fluid model by Dujko et al (2013 J. Phys. D 46 475202) We first review the fluid models: we briefly discuss their derivation, their underlying assumptions and the type of transport data they require. Then we compare these models to a particle-in-cell/Monte Carlo (PIC/MC) code, using a 1D test problem. The tests are performed in neon and nitrogen at standard temperature and pressure, over a wide range of reduced electric fields. For the fluid models, transport data generated by a multi-term Boltzmann solver are used. We analyze the observed differences in the model predictions and address some of the practical aspects when using these plasma fluid models

Numerical and experimental investigation of dielectric recovery in super-critical nitrogen

A supercritical (SC) nitrogen (N2) switch is designed and tested. The dielectric strength and recovery rate of the SC switch are investigated by experiments. In order to theoretically study the discharge and recovery process of the SC N2 switch under high repetition rate operation, a numerical model is developed. For SC N2 with initial parameters of p = 80.9 bar and T = 300 K, the simulation results show that within several nanoseconds after the streamer bridges the switch gap, the spark is fully developed and this time depends on the applied electric field between electrodes. During the whole discharge process, the maximum temperature in the channel is about 20 000 K. About 10μs after the spark excitation of 200 ns duration, the temperature on the axis decays to Taxis 1500 K, mainly contributed by the gas expansion and heat transfer mechanisms. After 100μs, the dielectric strength of the gap recovers to above half of the cold breakdown voltage due to the temperature decay in the channel. Both experimental and numerical investigations indicate that supercritical fluid is a good insulating medium that has a proved high breakdown voltage and fast recovery speed

Working of Section 153A of the Income Tax Act, 1961: Resolving the Conflict between the Literal Rule of Interpretation and Harmonious Construction

This article ventures into the various interpretations given by the court for the execution of Section 153A of the Income Tax Act, 1961. It has forever been a conflict as to how the particular section has to be interpreted, in order to decide whether the items of regular assessment can be added back in the proceeding under section 153A, after the finalization of assessment. This article tries to decode the mixed opinions of the court with regard to whether it is the literal rule of interpretation or the rule of harmonious construction that would apply to interpret Section 153A. This issue has been dealt with by the authors by analysing the various tools of interpretation of statutes like Literal Rule of Interpretation, reading down of statute as a whole, Rule of Harmonious Construction of statute etc. and their application in various cases based on judicial dicta of the court of law. The authors, based on thorough analysis of Section 153A, based on the language of the provision and the interpretations attached to it by the Judiciary, have tried to resolve the conflict between the Literal rule of interpretation and harmonious construction

High order fluid model for streamer discharges

A high order fluid model for streamer discharges is developed and used to investigate propagation of negative streamer fronts in N2 . Mo- mentum transfer theory is employed to evaluate the collision terms and close the system of moment/balance equations. The results of simulations are compared with those obtained by a PIC/MC method and by the classical first order fluid model based on the drif