Plasma Magnetic Insulation

Theoretically the strong magnetic field of a tokamak should confine electrons and ions in a high-temperature plasma sufficiently well. However, the behaviour of electrons turns out to be anomalous, especially with application of auxiliary heating. This behaviour is discussed in the framework of dimensional analysis and a hypothesis of plasma transition into a relaxed state with a minimal energy subjected to the single constraint, namely conservation of the total current. Plasma tends to relax to the optimal current-density and pressure profiles, any deviation from which results in a additional heat transfer via the micronoise pumping by the magnetic island structure. This effect is more pronounced with an increase of n/I_p, where n is the density, I_p is the plasma current.