Behavior of luminous clouds surrounding evaporating hydrogen and carbon pellets

The technique of tokamak magnetic field shear determination using the tilt of evaporating-pellet produced luminous clouds is described. Some differences in the techniques, involving either hydrogen or carbon pellets, are discussed. Two experimental methods of obtaining the safety factor profile are compared. The first of them involved luminous cloud tilt measurements, while the second one was based on injected carbon pellets toroidal acceleration. The safety factor measurements of both kinds were carried out within the same tokamak shot. The experimental results were also compared with theoretical calculations of the safety factor, based on an experimentally measured temperature profile and the assumption of Spitzer plasma conductivity. 8 refs., 2 figs.