ELM mitigation by nitrogen seeding in the JET gas box divertor

Rapp, J.; Herrmann, A.; Philipps, V.; Eich, T.; Jachmich, S.; Matthews, G. F.; von Hellermann, M.; Ingesson, L. C.; Saibene, G.

doi:10.1088/0741-3335/44/6/302

Journal Article

ELM mitigation by nitrogen seeding in the JET gas box divertor

Rapp, J.FZJ* ; Eich, T.FZJ* ; von Hellermann, M. ; Herrmann, A. ; Ingesson, L. C. ; Jachmich, S. ; Matthews, G. F. ; Philipps, V. ; Saibene, G.

2002
IOP Publ. Bristol

Plasma physics and controlled fusion 44, 639 - 652 (2002) [10.1088/0741-3335/44/6/302]

This record in other databases:

Please use a persistent id in citations: http://hdl.handle.net/2128/1767 doi:10.1088/0741-3335/44/6/302

Abstract: One of the most severe problems for fusion reactors is the power load on the divertor target plates. Technically only power loads of less than 10 MW m(-2) are acceptable. However, strong edge localized mode (ELM) activity can lead to power loads in excess of 800 MW m-2. In order to reduce the steady-state heat flux and the transient heat flux due to ELMS, radiation cooling experiments were performed at JET Nitrogen was puffed into the divertor up to a radiative power fraction of 90%. This was achieved at a density of 0.85 times the Greenwald density (Greenwald M 1988 Nucl. Fusion 28 2199), while maintaining an H-factor of f(H98) = 0.82. The Z(eff) in all those discharges stayed around 2.0. At approximately 55% radiative power fraction, the ELM characteristic changes from type I to type III, resulting in a loss of confinement of about 25% due to a degradation of the edge pedestal and hence a reduction of the ELM power load to the divertor tiles. By increasing the radiative power fraction to values of about 90%, the heat flux is reduced to 2 MW m(-2).

Keyword(s): J

Classification:

Note: Record converted from VDB: 12.11.2012

Contributing Institute(s):