Influence of a nonuniform field on the electron swarm parameters in SF6

The influence of a nonuniform electric field on the swarm parameters in SF₆ has been studied using the Monte Carlo simulation technique in which the motion of electrons is traced. Two field configurations in which the electrons move have been studied: increasing and decreasing electric fields. The spatial variations of the electron mean energy, drift velocity, ionization, and attachment coefficients are calculated for different field slopes and compared with the equilibrium values obtained under uniform field conditions. The results show that α/N is lower than the equilibrium value for increasing field and is higher for decreasing field with the relaxation rate depending on the field slope. The mean energy and drift velocity are almost the same as equilibrium values, while the attachment coefficients show a significant nonequilibrium feature