TY - JOUR
T1 - First measurements of electron temperature and density with divertor Thomson scattering in radiative divertor discharges on DIII-D
AU - Allen, S. L.
AU - Hill, D. N.
AU - Carlstrom, T. N.
AU - Nilson, D. G.
AU - Stockdale, R.
AU - Hsieh, C. L.
AU - Petrie, T. W.
AU - Leonard, A. W.
AU - Ryutov, D.
AU - Porter, G. D.
AU - Maingi, R.
AU - Wade, M. R.
AU - Cohen, R.
AU - Nevins, W.
AU - Fenstermacher, M. E.
PY - 1997/2/2
Y1 - 1997/2/2
N2 - We have obtained the first measurements of ne and Te in the DIII-D divertor region with a multi-pulse (20 Hz) divertor Thomson scattering (DTS) system. Eight measurement locations are distributed vertically up to 21 cm above the divertor plate. Two-dimensional distributions have been obtained by sweeping the divertor plasma across the DTS measurement location. Several operating modes have been studied, including Ohmic, L-mode, ELMing H-mode, and radiative divertor operation with puffing of D2 and impurities. Mapping of the data to either the (Lpol, π) or (R, Z) planes with the EFIT equilibrium is used to analyze the 2D profiles. We find that in ELMing H-mode: ne, Te and Pe are relatively constant along field lines from the X-point to the divertor plate, especially near the separatrix field line. With D2 puffing, the DTS profiles indicate that Te in a large part of divertor region below the X-point is dramatically reduced from approximately 30-40 eV in ELMing H-mode to 1-2 eV. This results in a fairly uniform low-Te divertor, with an increased electron density in the range of 2 to 4×1020 m+3. Detailed comparisons of the spatial profiles of ne, Te, and electron pressure Pe, are presented for several operating modes. In addition, these data are compared with initial calculations from the UEDGE fluid code.
AB - We have obtained the first measurements of ne and Te in the DIII-D divertor region with a multi-pulse (20 Hz) divertor Thomson scattering (DTS) system. Eight measurement locations are distributed vertically up to 21 cm above the divertor plate. Two-dimensional distributions have been obtained by sweeping the divertor plasma across the DTS measurement location. Several operating modes have been studied, including Ohmic, L-mode, ELMing H-mode, and radiative divertor operation with puffing of D2 and impurities. Mapping of the data to either the (Lpol, π) or (R, Z) planes with the EFIT equilibrium is used to analyze the 2D profiles. We find that in ELMing H-mode: ne, Te and Pe are relatively constant along field lines from the X-point to the divertor plate, especially near the separatrix field line. With D2 puffing, the DTS profiles indicate that Te in a large part of divertor region below the X-point is dramatically reduced from approximately 30-40 eV in ELMing H-mode to 1-2 eV. This results in a fairly uniform low-Te divertor, with an increased electron density in the range of 2 to 4×1020 m+3. Detailed comparisons of the spatial profiles of ne, Te, and electron pressure Pe, are presented for several operating modes. In addition, these data are compared with initial calculations from the UEDGE fluid code.
UR - http://www.scopus.com/inward/record.url?scp=6644221649&partnerID=8YFLogxK
U2 - 10.1016/S0022-3115(96)00571-5
DO - 10.1016/S0022-3115(96)00571-5
M3 - Conference article
AN - SCOPUS:6644221649
SN - 0022-3115
VL - 241-243
SP - 595
EP - 601
JO - Journal of Nuclear Materials
JF - Journal of Nuclear Materials
T2 - Proceedings of the 1996 12th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices
Y2 - 20 May 1996 through 24 May 1996
ER -