A semianalytical analysis of ion velocity distributions in the presence of combined neutral-beam and ICRF-Heating

The energy clamping scheme with combined neutral-beam and ICRF-heating is considered. Assuming the neutral-beam particles to be injected almost isotropically, an approximate equation is derived for the pitch angle averaged distribution function. Comparison between results obtained from this equation and those of a full 2D numerical calculation, shows good agreement for physically significant quantities, like total absorbed power, power transfer to background plasma particles and fusion reactivities. This indicates that the equation for the averaged distribution function should be useful in situations where time consuming 2D numerical calculations of the distribution function are impractical, e.g. in plasma transport codes