Charge exchange recombination spectroscopy for α particles colliding with hydrogen atoms

The intensities of charge exchange recombination spectroscopy (CXRS) of α particles colliding with the hydrogen atoms in the neutral beam injection (NBI) are calculated by solving the rate equations including electron collision processes in the quasi-static state approximation. The effects of electron collision processes on the CXRS signals for He+(n=4→3) at λ=468.6nm in various plasma conditions are discussed, and it is found that these effects can increase the CXRS signals by 50% for electron density ne≥1015cm-3. However, their importance decreases with the increasing of NBI energy. For the short pulse of NBI, the influences of electron collision processes can be neglected for ne≤1014cm-3. Furthermore, the spectra of He+(n→n') are present for the plasma conditions of HT-7 tokamak.