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Title: H-mode research in NSTX

Abstract

H-modes are routinely obtained in the National Spherical Torus Experiment (NSTX) and have become a standard operational scenario. L H transitions triggered by NBI heating have been obtained over a wide parameter range in I p, B t, and n¯ e in either lower-single-null (LSN) or double-null (DN) diverted discharges. Edge localized modes are observed in both configurations but the characteristics differ between DN and LSN, which also have different triangularities (δ). An H-mode duration of 500 ms was obtained in LSN, with a total pulse length of ~1 s. Preliminary power threshold studies indicate that the L–H threshold is between 600 kW and 1.2 MW, depending on the target parameters. Gas injector fuelling from the centre stack (i.e. the high toroidal field side) has enabled routine H-mode access, and comparisons with low-field side (LFS) fuelled H-mode discharges show that the LFS fuelling delays the L H transition and alters the pre-transition plasma profiles. Gas puff imaging and reflectometry show that the H-mode edge is usually more quiescent than the L-mode edge. Divertor infrared camera measurements indicate up to 70% of available power flows to the divertor targets in quiescent H-mode discharges.

Authors:
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Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1081832
DOE Contract Number:  
DE-AC05-00OR22725; AC02-76CH03073; AC04-94AL85000; W-7405- ENG-36; W-7405-ENG-48; FG02-99ER54524; FG02-99ER54523
Resource Type:
Journal Article
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 43; Journal Issue: 9; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English

Citation Formats

Maingi, R, Bell, M. G., Bell, R. E., Bush, C. E., Fredrickson, E. D., Gates, D. A., Gray, T, Johnson, D. W., Kaita, R, Kaye, S. M., Kubota, S, Kugel, H. W., Lasnier, C. J., LeBlanc, B. P., Maqueda, R. J., Mastrovito, D, Menard, J. E., Mueller, D., Ono, M., Paoletti, F., Paul, S. J., Peng, Y. -K.M, Roquemore, A. L., Sabbagh, S. A., Skinner, C. H., Soukhanovskii, V. A., Stutman, D., Swain, D. W., Synakowski, E. J., Tan, T., Wilgen, J. B., and Zweben, S. J. H-mode research in NSTX. United States: N. p., 2003. Web. doi:10.1088/0029-5515/43/9/322.
Maingi, R, Bell, M. G., Bell, R. E., Bush, C. E., Fredrickson, E. D., Gates, D. A., Gray, T, Johnson, D. W., Kaita, R, Kaye, S. M., Kubota, S, Kugel, H. W., Lasnier, C. J., LeBlanc, B. P., Maqueda, R. J., Mastrovito, D, Menard, J. E., Mueller, D., Ono, M., Paoletti, F., Paul, S. J., Peng, Y. -K.M, Roquemore, A. L., Sabbagh, S. A., Skinner, C. H., Soukhanovskii, V. A., Stutman, D., Swain, D. W., Synakowski, E. J., Tan, T., Wilgen, J. B., & Zweben, S. J. H-mode research in NSTX. United States. https://doi.org/10.1088/0029-5515/43/9/322
Maingi, R, Bell, M. G., Bell, R. E., Bush, C. E., Fredrickson, E. D., Gates, D. A., Gray, T, Johnson, D. W., Kaita, R, Kaye, S. M., Kubota, S, Kugel, H. W., Lasnier, C. J., LeBlanc, B. P., Maqueda, R. J., Mastrovito, D, Menard, J. E., Mueller, D., Ono, M., Paoletti, F., Paul, S. J., Peng, Y. -K.M, Roquemore, A. L., Sabbagh, S. A., Skinner, C. H., Soukhanovskii, V. A., Stutman, D., Swain, D. W., Synakowski, E. J., Tan, T., Wilgen, J. B., and Zweben, S. J. Mon . "H-mode research in NSTX". United States. https://doi.org/10.1088/0029-5515/43/9/322.
@article{osti_1081832,
title = {H-mode research in NSTX},
author = {Maingi, R and Bell, M. G. and Bell, R. E. and Bush, C. E. and Fredrickson, E. D. and Gates, D. A. and Gray, T and Johnson, D. W. and Kaita, R and Kaye, S. M. and Kubota, S and Kugel, H. W. and Lasnier, C. J. and LeBlanc, B. P. and Maqueda, R. J. and Mastrovito, D and Menard, J. E. and Mueller, D. and Ono, M. and Paoletti, F. and Paul, S. J. and Peng, Y. -K.M and Roquemore, A. L. and Sabbagh, S. A. and Skinner, C. H. and Soukhanovskii, V. A. and Stutman, D. and Swain, D. W. and Synakowski, E. J. and Tan, T. and Wilgen, J. B. and Zweben, S. J.},
abstractNote = {H-modes are routinely obtained in the National Spherical Torus Experiment (NSTX) and have become a standard operational scenario. L H transitions triggered by NBI heating have been obtained over a wide parameter range in I p, Bt, and n¯e in either lower-single-null (LSN) or double-null (DN) diverted discharges. Edge localized modes are observed in both configurations but the characteristics differ between DN and LSN, which also have different triangularities (δ). An H-mode duration of 500 ms was obtained in LSN, with a total pulse length of ~1 s. Preliminary power threshold studies indicate that the L–H threshold is between 600 kW and 1.2 MW, depending on the target parameters. Gas injector fuelling from the centre stack (i.e. the high toroidal field side) has enabled routine H-mode access, and comparisons with low-field side (LFS) fuelled H-mode discharges show that the LFS fuelling delays the L H transition and alters the pre-transition plasma profiles. Gas puff imaging and reflectometry show that the H-mode edge is usually more quiescent than the L-mode edge. Divertor infrared camera measurements indicate up to 70% of available power flows to the divertor targets in quiescent H-mode discharges.},
doi = {10.1088/0029-5515/43/9/322},
url = {https://www.osti.gov/biblio/1081832}, journal = {Nuclear Fusion},
issn = {0029-5515},
number = 9,
volume = 43,
place = {United States},
year = {2003},
month = {9}
}