Spectroscopic study of ECH and neutral beam injection heating of the Heliotron E plasma

VUV, UV and visible spectroscopy of fusion plasmas enables the main plasma contaminants to be identified, and time-resolved measurements allow a study of the development of the major impurity emission lines to be undertaken. In this work, Heliotron E VUV emission is shown to be dominated by oxygen, carbon, iron and nickel lines, and a scan of the emission in the UV-visible range reveals that the most intense impurity lines in this range are from boron, carbon and oxygen. A study of H alpha and D alpha emission from the plasma is carried out, and it is found that the release of hydrogen from the vessel wall is the dominant source of hydrogen in the discharge plasma. Preliminary spectroscopic results of lithium injection into the plasma are also presented. (C) 1997 Elsevier Science S.A.