Dipole Field Plasma Physics

The dipole field is the most elementary structure of a magnetic field and exists most frequently in nature. In spite of its relative simplicity of the structure, plasma behavior in the dipole field is complex both as a simple particle and as a fluid. For example a charged particle's motion is intrinsically chaotic even in the absence of an external field, while if an oscillatory field is applied, the Arnold diffusion can produce various nontrivial consequences. Equilibrium and stability of a finite beta plasma in the dipole field is another interesting subject which has relatively been less cultivated. I report recent progress in the development of plasma physics in the dipole magnetic field including an attempt of a laboratory experiment and its application to a fusion device.