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Title: Progress Towards High Performance, Steady-state Spherical Torus

Abstract

Research on the Spherical Torus (or Spherical Tokamak) is being pursued to explore the scientific benefits of modifying the field line structure from that in more moderate aspect-ratio devices, such as the conventional tokamak. The Spherical Tours (ST) experiments are being conducted in various U.S. research facilities including the MA-class National Spherical Torus Experiment (NSTX) at Princeton, and three medium-size ST research facilities: Pegasus at University of Wisconsin, HIT-II at University of Washington, and CDX-U at Princeton. In the context of the fusion energy development path being formulated in the U.S., an ST-based Component Test Facility (CTF) and, ultimately a Demo device, are being discussed. For these, it is essential to develop high-performance, steady-state operational scenarios. The relevant scientific issues are energy confinement, MHD stability at high beta (B), noninductive sustainment, ohmic-solenoid-free start-up, and power and particle handling. In the confinement area, the NSTX experiments have shown that the confinement can be up to 50% better than the ITER-98-pby2 H-mode scaling, consistent with the requirements for an ST-based CTF and Demo. In NSTX, CTF-relevant average toroidal beta values bT of up to 35% with the near unity central betaT have been obtained. NSTX will be exploring advanced regimes where bTmore » up to 40% can be sustained through active stabilization of resistive wall modes. To date, the most successful technique for noninductive sustainment in NSTX is the high beta-poloidal regime, where discharges with a high noninductive fraction ({approx}60% bootstrap current + neutral-beam-injected current drive) were sustained over the resistive skin time. Research on radio-frequency-based heating and current drive utilizing HHFW (High Harmonic Fast Wave) and EBW (Electron Bernstein Wave) is also pursued on NSTX, Pegasus, and CDX-U. For noninductive start-up, the Coaxial Helicity Injection (CHI), developed in HIT/HIT-II, has been adopted on NSTX to test the method up to Ip {approx} 500 kA. In parallel, start-up using radio-frequency current drive and only external poloidal field coils are being developed on NSTX. The area of power and particle handling is expected to be challenging because of the higher power density expected in the ST relative to that in conventional aspect-ratio tokamaks. Due to its promise for power and particle handling, liquid lithium is being studied in CDX-U as a potential plasma-facing surface for a fusion reactor.« less

Authors:
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Publication Date:
Research Org.:
Princeton Plasma Physics Lab., Princeton, NJ (US)
Sponsoring Org.:
USDOE Office of Science (SC) (US)
OSTI Identifier:
820078
Report Number(s):
PPPL-3876
TRN: US0305670
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 2 Oct 2003
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ASPECT RATIO; BOOTSTRAP CURRENT; CONFINEMENT; HARMONICS; HEATING; HELICITY; LITHIUM; PERFORMANCE; POWER DENSITY; STABILITY; STABILIZATION; START-UP; THERMONUCLEAR REACTORS; TOKAMAKS, NSTX; SPHERICAL TORUS; SPHERICAL TOKAMAK

Citation Formats

M. Ono, M.G. Bell, R.E. Bell, T. Bigelow, M. Bitter, W. Blanchard, J. Boedo, C. Bourdelle, C. Bush, W. Choe, J. Chrzanowski, D.S. Darrow, S.J. Diem, R. Doerner, P.C. Efthimion, J.R. Ferron, R.J. Fonck, E.D. Fredrickson, G.D. Garstka, D.A. Gates, T. Gray, L.R. Grisham, W. Heidbrink, K.W. Hill, D. Hoffman, T.R. Jarboe, D.W. Johnson, R. Kaita, S.M. Kaye, C. Kessel, J.H. Kim, M.W. Kissick, S. Kubota, H.W. Kugel, B.P. LeBlanc, K. Lee, S.G. Lee, B.T. Lewicki, S. Luckhardt, R. Maingi, R. Majeski, J. Manickam, R. Maqueda, T.K. Mau, E. Mazzucato, S.S. Medley, J. Menard, D. Mueller, B.A. Nelson, C. Neumeyer, N. Nishino, C.N. Ostrander, D. Pacella, F. Paoletti, H.K. Park, W. Park, S.F. Paul, Y.-K. M. Peng, C.K. Phillips, R. Pinsker, P.H. Probert, S. Ramakrishnan, R. Raman, M. Redi, A.L. Roquemore, A. Rosenberg, P.M. Ryan, S.A. Sabbagh, M. Schaffer, R.J. Schooff, R. Seraydarian, C.H. Skinner, A.C. Sontag, V. Soukhanovskii, J. Spaleta, T. Stevenson, D. Stutman, D.W. Swain, E. Synakowski, Y. Takase, X. Tang, G. Taylor, J. Timberlake, K.L. Tritz, E.A. Unterberg, A. Von Halle, J. Wilgen, M. Williams, J.R. Wilson, X. Xu, S.J. Zweben, R. Akers, R.E. Barry, P. Beiersdorfer, J.M. Bialek, B. Blagojevic, P.T. Bonoli, M.D. Carter, W. Davis, B. Deng, L. Dudek, J. Egedal, R. Ellis, M. Finkenthal, J. Foley, E. Fredd, A. Glasser, T. Gibney, M. Gilmore, R.J. Goldston, R.E. Hatcher, R.J. Hawryluk, W. Houlberg, R. Harvey, S.C. Jardin, J.C. Hosea, H. Ji, M. Kalish, J. Lowrance, L.L. Lao, F.M. Levinton, N.C. Luhmann, R. Marsala, D. Mastravito, M.M. Menon, O. Mitarai, M. Nagata, G. Oliaro, R. Parsells, T. Peebles, B. Peneflor, D. Piglowski, G.D. Porter, A.K. Ram, M. Rensink, G. Rewoldt, P. Roney, K. Shaing, S. Shiraiwa, P. Sichta, D. Stotler, B.C. Stratton, R. Vero, W.R. Wampler, and G.A. Wurden. Progress Towards High Performance, Steady-state Spherical Torus. United States: N. p., 2003. Web. doi:10.2172/820078.
M. Ono, M.G. Bell, R.E. Bell, T. Bigelow, M. Bitter, W. Blanchard, J. Boedo, C. Bourdelle, C. Bush, W. Choe, J. Chrzanowski, D.S. Darrow, S.J. Diem, R. Doerner, P.C. Efthimion, J.R. Ferron, R.J. Fonck, E.D. Fredrickson, G.D. Garstka, D.A. Gates, T. Gray, L.R. Grisham, W. Heidbrink, K.W. Hill, D. Hoffman, T.R. Jarboe, D.W. Johnson, R. Kaita, S.M. Kaye, C. Kessel, J.H. Kim, M.W. Kissick, S. Kubota, H.W. Kugel, B.P. LeBlanc, K. Lee, S.G. Lee, B.T. Lewicki, S. Luckhardt, R. Maingi, R. Majeski, J. Manickam, R. Maqueda, T.K. Mau, E. Mazzucato, S.S. Medley, J. Menard, D. Mueller, B.A. Nelson, C. Neumeyer, N. Nishino, C.N. Ostrander, D. Pacella, F. Paoletti, H.K. Park, W. Park, S.F. Paul, Y.-K. M. Peng, C.K. Phillips, R. Pinsker, P.H. Probert, S. Ramakrishnan, R. Raman, M. Redi, A.L. Roquemore, A. Rosenberg, P.M. Ryan, S.A. Sabbagh, M. Schaffer, R.J. Schooff, R. Seraydarian, C.H. Skinner, A.C. Sontag, V. Soukhanovskii, J. Spaleta, T. Stevenson, D. Stutman, D.W. Swain, E. Synakowski, Y. Takase, X. Tang, G. Taylor, J. Timberlake, K.L. Tritz, E.A. Unterberg, A. Von Halle, J. Wilgen, M. Williams, J.R. Wilson, X. Xu, S.J. Zweben, R. Akers, R.E. Barry, P. Beiersdorfer, J.M. Bialek, B. Blagojevic, P.T. Bonoli, M.D. Carter, W. Davis, B. Deng, L. Dudek, J. Egedal, R. Ellis, M. Finkenthal, J. Foley, E. Fredd, A. Glasser, T. Gibney, M. Gilmore, R.J. Goldston, R.E. Hatcher, R.J. Hawryluk, W. Houlberg, R. Harvey, S.C. Jardin, J.C. Hosea, H. Ji, M. Kalish, J. Lowrance, L.L. Lao, F.M. Levinton, N.C. Luhmann, R. Marsala, D. Mastravito, M.M. Menon, O. Mitarai, M. Nagata, G. Oliaro, R. Parsells, T. Peebles, B. Peneflor, D. Piglowski, G.D. Porter, A.K. Ram, M. Rensink, G. Rewoldt, P. Roney, K. Shaing, S. Shiraiwa, P. Sichta, D. Stotler, B.C. Stratton, R. Vero, W.R. Wampler, & G.A. Wurden. Progress Towards High Performance, Steady-state Spherical Torus. United States. doi:10.2172/820078.
M. Ono, M.G. Bell, R.E. Bell, T. Bigelow, M. Bitter, W. Blanchard, J. Boedo, C. Bourdelle, C. Bush, W. Choe, J. Chrzanowski, D.S. Darrow, S.J. Diem, R. Doerner, P.C. Efthimion, J.R. Ferron, R.J. Fonck, E.D. Fredrickson, G.D. Garstka, D.A. Gates, T. Gray, L.R. Grisham, W. Heidbrink, K.W. Hill, D. Hoffman, T.R. Jarboe, D.W. Johnson, R. Kaita, S.M. Kaye, C. Kessel, J.H. Kim, M.W. Kissick, S. Kubota, H.W. Kugel, B.P. LeBlanc, K. Lee, S.G. Lee, B.T. Lewicki, S. Luckhardt, R. Maingi, R. Majeski, J. Manickam, R. Maqueda, T.K. Mau, E. Mazzucato, S.S. Medley, J. Menard, D. Mueller, B.A. Nelson, C. Neumeyer, N. Nishino, C.N. Ostrander, D. Pacella, F. Paoletti, H.K. Park, W. Park, S.F. Paul, Y.-K. M. Peng, C.K. Phillips, R. Pinsker, P.H. Probert, S. Ramakrishnan, R. Raman, M. Redi, A.L. Roquemore, A. Rosenberg, P.M. Ryan, S.A. Sabbagh, M. Schaffer, R.J. Schooff, R. Seraydarian, C.H. Skinner, A.C. Sontag, V. Soukhanovskii, J. Spaleta, T. Stevenson, D. Stutman, D.W. Swain, E. Synakowski, Y. Takase, X. Tang, G. Taylor, J. Timberlake, K.L. Tritz, E.A. Unterberg, A. Von Halle, J. Wilgen, M. Williams, J.R. Wilson, X. Xu, S.J. Zweben, R. Akers, R.E. Barry, P. Beiersdorfer, J.M. Bialek, B. Blagojevic, P.T. Bonoli, M.D. Carter, W. Davis, B. Deng, L. Dudek, J. Egedal, R. Ellis, M. Finkenthal, J. Foley, E. Fredd, A. Glasser, T. Gibney, M. Gilmore, R.J. Goldston, R.E. Hatcher, R.J. Hawryluk, W. Houlberg, R. Harvey, S.C. Jardin, J.C. Hosea, H. Ji, M. Kalish, J. Lowrance, L.L. Lao, F.M. Levinton, N.C. Luhmann, R. Marsala, D. Mastravito, M.M. Menon, O. Mitarai, M. Nagata, G. Oliaro, R. Parsells, T. Peebles, B. Peneflor, D. Piglowski, G.D. Porter, A.K. Ram, M. Rensink, G. Rewoldt, P. Roney, K. Shaing, S. Shiraiwa, P. Sichta, D. Stotler, B.C. Stratton, R. Vero, W.R. Wampler, and G.A. Wurden. Thu . "Progress Towards High Performance, Steady-state Spherical Torus". United States. doi:10.2172/820078. https://www.osti.gov/servlets/purl/820078.
@article{osti_820078,
title = {Progress Towards High Performance, Steady-state Spherical Torus},
author = {M. Ono and M.G. Bell and R.E. Bell and T. Bigelow and M. Bitter and W. Blanchard and J. Boedo and C. Bourdelle and C. Bush and W. Choe and J. Chrzanowski and D.S. Darrow and S.J. Diem and R. Doerner and P.C. Efthimion and J.R. Ferron and R.J. Fonck and E.D. Fredrickson and G.D. Garstka and D.A. Gates and T. Gray and L.R. Grisham and W. Heidbrink and K.W. Hill and D. Hoffman and T.R. Jarboe and D.W. Johnson and R. Kaita and S.M. Kaye and C. Kessel and J.H. Kim and M.W. Kissick and S. Kubota and H.W. Kugel and B.P. LeBlanc and K. Lee and S.G. Lee and B.T. Lewicki and S. Luckhardt and R. Maingi and R. Majeski and J. Manickam and R. Maqueda and T.K. Mau and E. Mazzucato and S.S. Medley and J. Menard and D. Mueller and B.A. Nelson and C. Neumeyer and N. Nishino and C.N. Ostrander and D. Pacella and F. Paoletti and H.K. Park and W. Park and S.F. Paul and Y.-K. M. Peng and C.K. Phillips and R. Pinsker and P.H. Probert and S. Ramakrishnan and R. Raman and M. Redi and A.L. Roquemore and A. Rosenberg and P.M. Ryan and S.A. Sabbagh and M. Schaffer and R.J. Schooff and R. Seraydarian and C.H. Skinner and A.C. Sontag and V. Soukhanovskii and J. Spaleta and T. Stevenson and D. Stutman and D.W. Swain and E. Synakowski and Y. Takase and X. Tang and G. Taylor and J. Timberlake and K.L. Tritz and E.A. Unterberg and A. Von Halle and J. Wilgen and M. Williams and J.R. Wilson and X. Xu and S.J. Zweben and R. Akers and R.E. Barry and P. Beiersdorfer and J.M. Bialek and B. Blagojevic and P.T. Bonoli and M.D. Carter and W. Davis and B. Deng and L. Dudek and J. Egedal and R. Ellis and M. Finkenthal and J. Foley and E. Fredd and A. Glasser and T. Gibney and M. Gilmore and R.J. Goldston and R.E. Hatcher and R.J. Hawryluk and W. Houlberg and R. Harvey and S.C. Jardin and J.C. Hosea and H. Ji and M. Kalish and J. Lowrance and L.L. Lao and F.M. Levinton and N.C. Luhmann and R. Marsala and D. Mastravito and M.M. Menon and O. Mitarai and M. Nagata and G. Oliaro and R. Parsells and T. Peebles and B. Peneflor and D. Piglowski and G.D. Porter and A.K. Ram and M. Rensink and G. Rewoldt and P. Roney and K. Shaing and S. Shiraiwa and P. Sichta and D. Stotler and B.C. Stratton and R. Vero and W.R. Wampler and G.A. Wurden},
abstractNote = {Research on the Spherical Torus (or Spherical Tokamak) is being pursued to explore the scientific benefits of modifying the field line structure from that in more moderate aspect-ratio devices, such as the conventional tokamak. The Spherical Tours (ST) experiments are being conducted in various U.S. research facilities including the MA-class National Spherical Torus Experiment (NSTX) at Princeton, and three medium-size ST research facilities: Pegasus at University of Wisconsin, HIT-II at University of Washington, and CDX-U at Princeton. In the context of the fusion energy development path being formulated in the U.S., an ST-based Component Test Facility (CTF) and, ultimately a Demo device, are being discussed. For these, it is essential to develop high-performance, steady-state operational scenarios. The relevant scientific issues are energy confinement, MHD stability at high beta (B), noninductive sustainment, ohmic-solenoid-free start-up, and power and particle handling. In the confinement area, the NSTX experiments have shown that the confinement can be up to 50% better than the ITER-98-pby2 H-mode scaling, consistent with the requirements for an ST-based CTF and Demo. In NSTX, CTF-relevant average toroidal beta values bT of up to 35% with the near unity central betaT have been obtained. NSTX will be exploring advanced regimes where bT up to 40% can be sustained through active stabilization of resistive wall modes. To date, the most successful technique for noninductive sustainment in NSTX is the high beta-poloidal regime, where discharges with a high noninductive fraction ({approx}60% bootstrap current + neutral-beam-injected current drive) were sustained over the resistive skin time. Research on radio-frequency-based heating and current drive utilizing HHFW (High Harmonic Fast Wave) and EBW (Electron Bernstein Wave) is also pursued on NSTX, Pegasus, and CDX-U. For noninductive start-up, the Coaxial Helicity Injection (CHI), developed in HIT/HIT-II, has been adopted on NSTX to test the method up to Ip {approx} 500 kA. In parallel, start-up using radio-frequency current drive and only external poloidal field coils are being developed on NSTX. The area of power and particle handling is expected to be challenging because of the higher power density expected in the ST relative to that in conventional aspect-ratio tokamaks. Due to its promise for power and particle handling, liquid lithium is being studied in CDX-U as a potential plasma-facing surface for a fusion reactor.},
doi = {10.2172/820078},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2003},
month = {10}
}