D. Farina et al., LIMITED STOCHASTIC ELECTRON ACCELERATION INDUCED BY AN INTENSE CYCLOTRON WAVE IN A PLASMA, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 47(5), 1993, pp. 2995-2998
An investigation of the stochastic electron acceleration in a magnetiz
ed plasma due to an intense electron cyclotron wave is performed for t
he case of a stochastic regime where only a few resonances overlap and
the stochastic region in phase space is bounded. The electron dynamic
s is described by a Hamiltonian function H(theta,I,t), and the stochas
tic properties of the system are investigated by means of the Poincare
-section method and the analytical estimates of the phase-correlation
function. The behavior of the system is then analyzed through the Fokk
er-Planck-Kolmogorov (FPK) diffusion equation in action space. The the
oretical FPK predictions are compared with the results of a numerical
simulation of the particle motion. It is found that the system satisfi
es the diffusion equation at times that are short compared to the satu
ration time of the quasilinear diffusion. Appreciable deviations from
the diffusive results are found at longer times, since the particle mo
tion is influenced by the region of local stochasticity in phase space
.