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Title: Effect of Gas Fueling Location on H-mode Access in NSTX

Abstract

The dependence of H-mode access on the poloidal location of the gas injection source has been investigated in the National Spherical Torus Experiment (NSTX). We find that gas fueling from the center stack midplane area produces the most reproducible H-mode access with generally the lowest L-H threshold power in lower single-null configuration. The edge toroidal rotation velocity is largest (in direction of the plasma current) just before the L-H transition with center stack midplane fueling, and then reverses direction after the L-H transition. Simulation of these results with a 2-D guiding-center Monte Carlo neoclassical transport code is qualitatively consistent with the trends in the measured velocities. Double-null discharges exhibit H-mode access with gas fueling from either the center stack midplane or center stack top locations, indicating a reduced sensitivity of H-mode access on fueling location in that shape.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Princeton Plasma Physics Lab., NJ (US)
Sponsoring Org.:
USDOE Office of Science (SC) (US)
OSTI Identifier:
820105
Report Number(s):
PPPL-3883
TRN: US0305682
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 9 Oct 2003
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CONFIGURATION; ELECTRIC CURRENTS; GAS INJECTION; ROTATION; SENSITIVITY; SHAPE; SIMULATION; TRANSPORT; VELOCITY; EDGE PLASMA; H-MODE PLASMA CONFINEMENT; TOKAMAKS, NSTX

Citation Formats

R. Maingi, M. Bell, R. Bell, T. Biewer, C. Bush, C.S. Chang, D. Gates, S. Kaye, H. Kugel, B. LeBlanc, R. Maqueda, J. Menard, D. Mueller, R. Raman, S. Sabbagh, V. Soukhanovskii, and the NSTX Team. Effect of Gas Fueling Location on H-mode Access in NSTX. United States: N. p., 2003. Web. doi:10.2172/820105.
R. Maingi, M. Bell, R. Bell, T. Biewer, C. Bush, C.S. Chang, D. Gates, S. Kaye, H. Kugel, B. LeBlanc, R. Maqueda, J. Menard, D. Mueller, R. Raman, S. Sabbagh, V. Soukhanovskii, & the NSTX Team. Effect of Gas Fueling Location on H-mode Access in NSTX. United States. doi:10.2172/820105.
R. Maingi, M. Bell, R. Bell, T. Biewer, C. Bush, C.S. Chang, D. Gates, S. Kaye, H. Kugel, B. LeBlanc, R. Maqueda, J. Menard, D. Mueller, R. Raman, S. Sabbagh, V. Soukhanovskii, and the NSTX Team. Thu . "Effect of Gas Fueling Location on H-mode Access in NSTX". United States. doi:10.2172/820105. https://www.osti.gov/servlets/purl/820105.
@article{osti_820105,
title = {Effect of Gas Fueling Location on H-mode Access in NSTX},
author = {R. Maingi and M. Bell and R. Bell and T. Biewer and C. Bush and C.S. Chang and D. Gates and S. Kaye and H. Kugel and B. LeBlanc and R. Maqueda and J. Menard and D. Mueller and R. Raman and S. Sabbagh and V. Soukhanovskii and the NSTX Team},
abstractNote = {The dependence of H-mode access on the poloidal location of the gas injection source has been investigated in the National Spherical Torus Experiment (NSTX). We find that gas fueling from the center stack midplane area produces the most reproducible H-mode access with generally the lowest L-H threshold power in lower single-null configuration. The edge toroidal rotation velocity is largest (in direction of the plasma current) just before the L-H transition with center stack midplane fueling, and then reverses direction after the L-H transition. Simulation of these results with a 2-D guiding-center Monte Carlo neoclassical transport code is qualitatively consistent with the trends in the measured velocities. Double-null discharges exhibit H-mode access with gas fueling from either the center stack midplane or center stack top locations, indicating a reduced sensitivity of H-mode access on fueling location in that shape.},
doi = {10.2172/820105},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Oct 09 00:00:00 EDT 2003},
month = {Thu Oct 09 00:00:00 EDT 2003}
}

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