Breakdown Electric Field of Hot 30% CF_3I/CO_2 Mixtures at Temperature of 300–3500 K During Arc Extinction Process

We calculated the uniform dielectric breakdown field strength of residual 30% CF3I/CO2 gas mixtures during the arc extinction process over the temperature range 300-3500 K at 0.1 MPa. The limiting reduced field strengths are decided by a balance of electron generation and loss based on chemical reactions estimated by the electron energy distribution function （EEDF）, which employs the Boltzmann equation method with two-term expanding approximation in the steady-state Townsend （SST） condition. During the insulation recovery phase, the hot CF3I/CO2 gas mixtures have maximum dielectric strength at a temperature of about 1500 K. At room temperature 300 K, the electric strength after arc extinction （90.3 Td, 1 Td=10-21 V.m2） is only 38% of the original value before arc （234.9 Td）. The adverse insulation recovery ability of CF3I/CO2 gas mixtures in arc extinction hinders its application in electric circuit breakers and other switchgears as an arc quenching and insulating medium.

Thermoelectric response of spin polarization in Rashba spintronic systems

Motivated by the recent discovery of a strongly spin-orbit-coupled two-dimensional （2D） electron gas near the surface of Rashba semiconductors BiTeX （X = Cl, Br, I）, we calculate the thermoelectric responses of spin polarization in a 2D Rashba model. By self-consistently determining the energy- and band-dependent transport time, we present tion for elastic scattering. Using this solution, an exact solution of the linearized Boltzmann equa- we find a non-Edelstein electric-field-induced spin polarization that is linear in the Fermi energy EF when EF lies below the band crossing point. The spin polarization efficiency, which is the electric-field-induced spin polarization divided by the driven electric current, increases for smaller EF. We show that, as a function of EF, the temperature- gradient-induced spin polarization increases continuously to a saturation value when EF decreases below the band crossing point. As the temperature tends to zero, the temperature-gradient-induced spin polarization vanishes.

High order moment closure for Vlasov-Maxwell equations

The extended magnetohydrodynamic models are derived based on the moment closure of the Vlasov-Maxwell （VM） equations. We adopt the Grad type moment expansion which was firstly proposed for the Boltzmann equation. A new regularization method for the Grad＇s moment system was recently proposed to achieve the globally hyperbolicity so that the local well-posedness of the moment system is attained. For the VM equations, the moment expansion of the convection term is exactly the same as that in the Boltzmann equation, thus the new developed regularization applies. The moment expansion of the electromagnetic force term in the VM equations turns out to be a linear source term, which can preserve the conservative properties of the distribution function in the VM equations perfectly.