Abstract
The radiation of divertor heat flux on DIII-D [J. Luxon et al, in Proceedings of the 11th International Conference on Plasma Physics and Controlled Nuclear Fusion (International Atomic Energy Agency, Vienna, 1987), p. 159] is shown to greatly exceed the limits imposed by assumptions of energy transport dominated by electron thermal conduction parallel to the magnetic field. Approximately 90% of the power flowing into the divertor is dissipated through low-Z radiation and plasma recombination. The dissipation is made possible by an extended region of low electron temperature in the divertor. A one-dimensional analysis of the parallel heat flux finds that the electron temperature profile is incompatible with conduction-dominated parallel transport. Plasma flow at up to the ion acoustic speed, produced by upstream ionization, can account for the parallel heat flux. Modeling with the two-dimensional fluid code UEDGE [T. Rognlien, J. L. Milovich, M. E. Rensink, and G. D. Porter, J. Nucl. Mater. 196-198, 347 (1992)] has reproduced many of the observed experimental features.
Original language | English |
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Pages (from-to) | 1736-1743 |
Number of pages | 8 |
Journal | Physics of Plasmas |
Volume | 5 |
Issue number | 5 PART 1 |
DOIs | |
State | Published - May 1998 |