The influence of non-standard orbits on ICRH power deposition in tokamaks

The distribution function and power deposition during ICRH in a tokamak plasma are analysed. The importance of self-consistent calculations and the formation of nonstandard drift orbits are addressed. It is found that for high power ICRH, the presence of non-standard orbits are crucial for describing the distribution function. For a standard minority heating scenario with the ion cyclotron resonance located at the high field side, the absorption of the wave power is shifted to the low field side (LFS) because of the orbit topology and the evolving wave field profile. The high energy tail of the distribution function of the resonating ions is found to be dominated by ions in passing orbits, of which some reside completely on the LFS of the tokamak.