Stochastic E×B Particle Transport

Phys. Fluids 27, 1686 (1984)https://ireap.umd.edu/10.1063/1.8648231984Journal ArticlePlasma, Accelerator, and Nuclear Physics

The E×B particle guiding center motion caused by two propagating electrostatic waves is investigated. Particle motion is stochastic if three criteria are met: (1) the phase velocities of the two waves are not equal, (2) the E×B drift velocities generated by each wave are nearly the same, and (3) the total E×B drift velocity is larger than the phase velocity of each wave. Particle transport in the stochastic regime is distinguished by three important characteristics: (1) the diffusion coefficient is virtually independent of the electric field fluctuation amplitude Ẽ at large Ẽ, (2) particle transport is generated only by waves which produce nearly commensurate E×B drifts, and (3) the velocity correlation time does not depend on Ẽ, but rather on the wave periods. The physical mechanism underlying stochastic particle transport is discussed. At large Ẽ the transport is dominated by a small group of particles which make long jumps along the separatrix of the potential contours of the waves.