Spectroscopic investigation of a reversed field pinch operated without limiters

Spectroscopic measurements on the ZT-40M reversed field pinch [submitted to Fusion Tech.] discharge are reported. Specifically, the impurity content, Zeff, recycling behavior, ion temperature, and propagation of magnetohydrodynamic modes in the edge are addressed. The importance of the plasma–wall interaction in ZT-40M, operated without limiters, is demonstrated.