Ion temperature profile measurements using the far line wings of Hα

We present 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 remaining intensity in the profile originates in the hottest portion of the line of sight, thus removing the need for an inversion procedure. A scanning Fabry–Perot interferometer is used to measure the line profiles because of its superior instrumental profile. This technique and its results will be compared with the charge-exchange technique and impurity Doppler broadening results. The application to ion temperature measurements using a diagnostic neutral beam will also be discussed.