Toroidal rotation of hydrogen in the RTP tokamak

Abstract

With a high resolution visible light spectrometer the Hα emission at the RTP tokamak has been studied. Monitoring the Hα line (6562.8 Å) with a toroidal line of sight into the plasma shows spectra with intricate Hα line structures. These line profiles can be explained by the occurrence of three different velocity groups of excited hydrogen with relative line shifts of the order of 2 Å. The origin of these three groups results from collisional processes with species of hydrogen, namely neutral hydrogen, H+ and also H2+ molecules.