ICRF heating of a D+ plasma with a minority H+ component in DIVA

ICRF heating of impurity-free tokamak plasmas is studied in DIVA. The frequency is fixed at 25 MHz, which is a second-harmonic cyclotron frequency of deuteron with a toroidal magnetic field of 16.4 kG. The toroidal field Bsub(T) and the ratio of proton-to-deuteron density epsilonsub(p) are varied over ranges of 12<=Bsub(T)<=19 kG and 2 approximately <epsilonsub(p) approximately <40%, respectively. The most favourable ion heating is obtained at Bsub(T)=18 kG and epsilonsub(p)=5 approximately 10%. Ion temperature increases from 200 to 300 eV were measured by charge-exchange neutral analysis and also by spectroscopy, where 100 kW RF net power were applied. The results are consistent with mode-conversion theory. (author)