Ion temperature profile measurements using the far line wings of Hα

This paper presents ion temperature profiles for the outer half of the TEXT plasma using the Doppler broadened far line wings of the Hα line profile. The technique depends on the assumption that the hydrogen neutrals have equilibrated with the ions through charge exchange collisions. Data reduction depends upon going far enough out on the line wing that the intensity profile is characteristic of the hottest portion of the plasma along the line of sight, thus removing the need for an inversion procedure. A Fabry-Perot interferometer is used to measure the line profiles because of its superior instrumental profile. This technique is compared with the charge exchange technique and Doppler broadening of impurities. The application to ion temperature measurements using a diagnostic neutral beam is also discussed