Charged-Particle Orbits in Sheared Magnetic Fields; Implications to Diffusion

Abstract

Charged-particle motion across a sheared magnetic field and electrostatic wave is studied. Resonant-particle orbit widths are derived; two parametric dependences are found in the limits that the particle is near or far from the k/sub parallel/=0 plane, with a smooth transition between the two. The orbit widths are used to calculate diffusion coefficients in tokamak-type configurations. These predictions are confirmed by test-particle computer simulations in (x, y, v/subx/, v/suby/, v/subz/) coordinates employing a Monte Carlo collision operator. (AIP)