No abstract

Chemical equilibrium is considered for atoms, molecules and clusters located in a bu †er gas of the positive column of an arc of high pressure. Because of the temperature variation, regions of atoms, molecules and clusters are separated in the discharge tube, and the sizes of the transition regions are determined by di †usion processes in the bu †er gas. It is shown that the chemical compound in a low temperature region depends on the partial pressure of additions. If clusters are formed in an intermediate discharge region, an instability occurs due to the small di †usivity of clusters. This instability leads to transformation of atoms in clusters which size tends to inÐnity.

The review is devoted to the discussion of the role of trapped particles for equilibrium, diffusion and stability of plamas in toroidal magnetic devices. The motion of single particles in a toroidal magnetic field, the neoclassical transport processes due to the trapping of particles and trapped-particle instabilities in toroidal geometry are discussed. The correspondence between the neoclassical theory of diffusion, the turbulent transport processes due to the instabilities and the existing experimental Tokamak data is discussed.

In summarizing the results of this Conference, the first fact we note is that transition to toroidal machines is nearly complete now in both high- and low-β physics, with one exception, – the mirror machines.