Generation of fast electrons in reversed field pinches by the equilibrium grad (vert bar)B(vert bar) force

摘要

It is shown that a decreasing magnetic field profile in reversed-field pinch plasmas leads to formation of an anisotropic electron distribution function at the plasma edge. The mechanism is the conservation of the magnetic moment and the energy of electrons that collisionlessly travel outward in a stochastic magnetic field. As a result, the electrons have high parallel energies and low perpendicular energies at the edge. The details of the distribution function correspond well to experimental results.