Fusion product energy spectra in beam heated D-D, D-T, and D-3He plasmas

One of the critical parameters in large scale fusion experiments is the ion speed distribution and its variation with changes in confinement and heating. Large plasma dimensions and high densities complicate direct measurement of this distribution since ions escaping to the wall are primarily those which undergo charge exchange in the outer plasma or those which have suffered many collisions and significant energy loss during their migration from the central plasma. Several previous works have shown that neutron and proton fusion reaction products generate a spectral line which is fairly broad due to Doppler broadening