Comparison of relativistic runaway electron avalanche rates obtained from Monte Carlo simulations and kinetic equation solution

New computer simulations of the relativistic runaway electron avalanche mechanism were carried out to remove prior approximations and reassess the space and temporal scales predicted by previous Boltzmann calculations. Two Monte Carlo techniques, a finite-difference solution, and a finite-volume solution of the kinetic equation for high-energy electrons were employed. Results obtained for the length and time scales at sufficiently high electric fields by the different methods are consistent with each other and with analytical estimates. The physical reason for the remaining discrepancy at small fields is discussed.