I-V characteristics of foilless diodes

Some physical characteristics of foiless diodes are obtained and analyzed by numerical simulations. Relations between diode current and configuration parameters, diode voltage and external magnetic field are investigated. Employing these relations and assuming that the external magnetic field is intense enough, the diode current can be approximately written as I_\rm b=(7.5/x)(x+(0.81-x)/(1+0.7L_\rm d^2/\delta r))(\gamma_0^2/3-1)^3/2, in which L_\rm d is the Anode-Cathode (AK) gap, R_\rm c the outer radius of cathode, and R_\rm p the radius of drifting tube; x=\ln(R_\rm p/R_\rm c)，\delta r =R_\rm p-R_\rm c . This expression is comparatively accurate for with different configuration parameters and voltages, results obtained from this expression are consistent with that of numerical simulations within an error of 10%.