JET-P(93)86
Heat Transport with Strong On and Off-Axis Heating
A series of further experiments was undertaken on JET in 1992 to investigate if the transport of heat in a tokamak is local and diffusive. These experiments consisted of applying minority Ion Cyclotron Resonance Heating (ICRH) to similar 3MA, 2.2T L-mode discharges in which the resonance was located on-axis and 0.5m off-axis. Combined on-and off-axis experiments were also undertaken. Two different types of discharge were used, the first one was a conventional edge fuelled discharge and in the second type the discharge was pellet fuelled prior to the onset of the heating. The purpose of the pellet fuelling was to provide a large central heat sink such that there was a significant region in which the heat flux is inward (i.e. negative).