ASYMMETRY OF RADIAL HEAT PULSE-PROPAGATION AT TEXTOR

Electron heat pulse propagation following sawtooth collapse has been simultaneously observed along two opposite radial directions. For a given flux surface, the arrival of the heat pulse at the high field side (HFS) is delayed by up to 1 ms as compared with the arrival at the low field side (LFS). The observed delay agrees with an estimate of the time required for parallel electron heat transport along the magnetic field lines connecting the corresponding LFS and HFS isobars. This suggests that the primary radial heat transport occurs on the LFS, whereas the HFS is fed subsequently from the LFS by temperature equilibration along the connecting magnetic field lines.