Evidence for the importance of radial transport in plasma detachment in the Nagoya University Divertor Simulator (NAGDIS-II)
Measurements of ion and electron temperatures have been performed in detaching helium--hydrogen plasmas in a linear divertor simulator experiment using spectroscopy, a Langmuir probe, and an omegatron mass spectrometer. Detachment in these plasmas is characterized by a significant ({approx}20 x) reduction in the central plasma flux at the target plate as the target region neutral pressure is increased from 2 to 12 mTorr. The data indicate that partially detached gas-target plasmas consist of a hot (T{sub e}{approx}5 eV) core region along the axis of the plasma column, surrounded by a cold (T{sub e}{approx}0.1 eV) halo region of recombining plasma. At T{sub e}=5 eV, plasma recombination is negligible compared with ionization; these experiments therefore provide evidence that detachment is primarily caused by radial transport and by a gradual drop in the ionization source as the temperature of the core region drops below 5 eV.
- Sponsoring Organization:
- (US)
- DOE Contract Number:
- FG03-95ER54301
- OSTI ID:
- 40277825
- Journal Information:
- Physics of Plasmas, Vol. 8, Issue 7; Other Information: DOI: 10.1063/1.1372664; Othernumber: PHPAEN000008000007003314000001; 006107PHP; PBD: Jul 2001; ISSN 1070-664X
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
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