Numerical studies of minority heating current drive

It was proposed that electric current could be generated by asymmetric heating of minority ions traveling in one direction without any net momentum injected into the system. The most important step for the operation of this scheme is the inducement of the toroidal drift of the minority ion species relative to the majority ion species. This process is studied numerically by solving Fokker-Planck equation in which the quasilinear diffusion term for asymmetric cyclotron absorption is added to the coulomb collision terms between minority ions and background particles (majority ions and electrons). The plasma studied included He/sup 3/-D and H-D where deuterium is the majority ion species. The results show that a minority ion drift can be induced by asymmetric cyclotron heating. The case for the one-species hydrogen plasma with the existence of impurity ions, which are in practice difficult to be suppressed, is is discussed. The details for the evolution of the distribution function in the velocity space and total current generated are presented