Physics of Plasmas in a Dipole Field

Dipole field is the most elementary structure of a magnetic field, yet the behavior of a plasma in a dipole magnetic field is very interesting both from the point of view of a single particle motion and of a collective fluid motion. In particular when a stochastic motion and diffusion in psi-phi space is induced by RF fields at omega~mphi the plasma particles are expected to have an ambipolar diffusion toward the center of the dipole and simultaneously be heated by J and mu conservations. Here mu, J and psi are the first (the magnetic moment), the second (action of the bounce motion) and the third (magnetic flux) invariants, phi is the conjugate angle of psi and m is the azimuthal mode number of the RF.