Overview of recent alcator C-Mod research

E.S. Marmar; B. Bai; R.L. Boivin; P.T. Bonoli; C. Boswell; R. Bravenec; B. Carreras; D. Ernst; C. Fiore; S. Gangadhara; K. Gentle; J. Goetz; R. Granetz; M. Greenwald; K. Hallatschek; J. Hastie; J. Hosea; A. Hubbard; J.W. Hughes; I. Hutchinson; Y. In; J. Irby; T. Jennings; D. Kopon; G. Kramer; B. LaBombard; W.D. Lee; Y. Lin; B. Lipschultz; J. Liptac; A. Lynn; K. Marr; R. Maqueda; E. Melby; D. Mikkelsen; D. Mossessian; R. Nazikian; W.M. Nevins; R. Parker; T.S. Pedersen; C.K. Phillips; P. Phillips; C.S. Pitcher; M. Porkolab; J. Ramos; M. Redi; J. Rice; B.N. Rogers; W.L. Rowan; M. Sampsell; G. Schilling; S. Scott; J. Snipes; P. Snyder; D. Stotler; G. Taylor; J.L. Terry; H. Wilson; J.R. Wilson; S.M. Wolfe; S. Wukitch; X.Q. Xu; B. Youngblood; H. Yuh; K. Zhurovich; S. Zweben; Bruce Lipschultz

doi:10.1088/0029-5515/43/12/007

Overview of recent alcator C-Mod research

E.S. Marmar, B. Bai, R.L. Boivin, P.T. Bonoli, C. Boswell, R. Bravenec, B. Carreras, D. Ernst, C. Fiore, S. Gangadhara, K. Gentle, J. Goetz, R. Granetz, M. Greenwald, K. Hallatschek, J. Hastie, J. Hosea, A. Hubbard, J.W. Hughes, I. HutchinsonY. In, J. Irby, T. Jennings, D. Kopon, G. Kramer, B. LaBombard, W.D. Lee, Y. Lin, B. Lipschultz, J. Liptac, A. Lynn, K. Marr, R. Maqueda, E. Melby, D. Mikkelsen, D. Mossessian, R. Nazikian, W.M. Nevins, R. Parker, T.S. Pedersen, C.K. Phillips, P. Phillips, C.S. Pitcher, M. Porkolab, J. Ramos, M. Redi, J. Rice, B.N. Rogers, W.L. Rowan, M. Sampsell, G. Schilling, S. Scott, J. Snipes, P. Snyder, D. Stotler, G. Taylor, J.L. Terry, H. Wilson, J.R. Wilson, S.M. Wolfe, S. Wukitch, X.Q. Xu, B. Youngblood, H. Yuh, K. Zhurovich, S. Zweben, Bruce Lipschultz

Physics

Research output: Contribution to journal › Article › peer-review

Abstract

Research on the Alcator C-Mod tokamak [1] is focused on high particle- and power-density plasma regimes to understand particle and energy transport in the core, the dynamics of the H-mode pedestal, and scrape-off layer and divertor physics. The auxiliary heating is provided exclusively by RF waves, and both the physics and technology of RF heating and current drive are studied. The momentum which is manifested in strong toroidal rotation, in the absence of direct momentum input, has been shown to be transported in from the edge of the plasma following the L-H transition, with timescale comparable to that for energy transport. In discharges which develop internal transport barriers, the rotation slows first inside the barrier region, and then subsequently outside of the barrier foot. Heat pulse propagation studies using sawteeth indicate a very narrow region of strongly reduced energy transport, located near r/a = 0.5. Addition of on-axis ICRF heating arrests the buildup of density and impurities, leading to quasi-steady conditions. The quasi-coherent mode associated with enhanced D-Alpha (EDA) H-mode appears to be due to a resistive ballooning instability. As the pedestal pressure gradient and temperature are increased in EDA H-mode, small ELMs appear; detailed modelling indicates that these are due to intermediate n peeling-ballooning modes. Phase contrast imaging has been used to directly detect density fluctuations driven by ICRF waves in the core of the plasma, and mode conversion to an intermediate wavelength ion cyclotron wave has been observed for the first time. The bursty turbulent density fluctuations, observed to drive rapid cross-field particle transport in the edge plasma, appear to play a key role in the dynamics of the density limit. Preparations for quasi-steady-state advanced tokamak studies with lower hybrid current drive are well underway, and time dependent modelling indicates that regimes with high bootstrap fraction can be produced.

Original language	English
Pages (from-to)	1610-1618
Number of pages	9
Journal	Nuclear Fusion
Volume	43
Issue number	12
DOIs	https://doi.org/10.1088/0029-5515/43/12/007
Publication status	Published - 1 Dec 2003

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10.1088/0029-5515/43/12/007

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Marmar, E. S., Bai, B., Boivin, R. L., Bonoli, P. T., Boswell, C., Bravenec, R., Carreras, B., Ernst, D., Fiore, C., Gangadhara, S., Gentle, K., Goetz, J., Granetz, R., Greenwald, M., Hallatschek, K., Hastie, J., Hosea, J., Hubbard, A., Hughes, J. W., ... Lipschultz, B. (2003). Overview of recent alcator C-Mod research. Nuclear Fusion, 43(12), 1610-1618. https://doi.org/10.1088/0029-5515/43/12/007

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title = "Overview of recent alcator C-Mod research",

abstract = "Research on the Alcator C-Mod tokamak [1] is focused on high particle- and power-density plasma regimes to understand particle and energy transport in the core, the dynamics of the H-mode pedestal, and scrape-off layer and divertor physics. The auxiliary heating is provided exclusively by RF waves, and both the physics and technology of RF heating and current drive are studied. The momentum which is manifested in strong toroidal rotation, in the absence of direct momentum input, has been shown to be transported in from the edge of the plasma following the L-H transition, with timescale comparable to that for energy transport. In discharges which develop internal transport barriers, the rotation slows first inside the barrier region, and then subsequently outside of the barrier foot. Heat pulse propagation studies using sawteeth indicate a very narrow region of strongly reduced energy transport, located near r/a = 0.5. Addition of on-axis ICRF heating arrests the buildup of density and impurities, leading to quasi-steady conditions. The quasi-coherent mode associated with enhanced D-Alpha (EDA) H-mode appears to be due to a resistive ballooning instability. As the pedestal pressure gradient and temperature are increased in EDA H-mode, small ELMs appear; detailed modelling indicates that these are due to intermediate n peeling-ballooning modes. Phase contrast imaging has been used to directly detect density fluctuations driven by ICRF waves in the core of the plasma, and mode conversion to an intermediate wavelength ion cyclotron wave has been observed for the first time. The bursty turbulent density fluctuations, observed to drive rapid cross-field particle transport in the edge plasma, appear to play a key role in the dynamics of the density limit. Preparations for quasi-steady-state advanced tokamak studies with lower hybrid current drive are well underway, and time dependent modelling indicates that regimes with high bootstrap fraction can be produced.",

author = "E.S. Marmar and B. Bai and R.L. Boivin and P.T. Bonoli and C. Boswell and R. Bravenec and B. Carreras and D. Ernst and C. Fiore and S. Gangadhara and K. Gentle and J. Goetz and R. Granetz and M. Greenwald and K. Hallatschek and J. Hastie and J. Hosea and A. Hubbard and J.W. Hughes and I. Hutchinson and Y. In and J. Irby and T. Jennings and D. Kopon and G. Kramer and B. LaBombard and W.D. Lee and Y. Lin and B. Lipschultz and J. Liptac and A. Lynn and K. Marr and R. Maqueda and E. Melby and D. Mikkelsen and D. Mossessian and R. Nazikian and W.M. Nevins and R. Parker and T.S. Pedersen and C.K. Phillips and P. Phillips and C.S. Pitcher and M. Porkolab and J. Ramos and M. Redi and J. Rice and B.N. Rogers and W.L. Rowan and M. Sampsell and G. Schilling and S. Scott and J. Snipes and P. Snyder and D. Stotler and G. Taylor and J.L. Terry and H. Wilson and J.R. Wilson and S.M. Wolfe and S. Wukitch and X.Q. Xu and B. Youngblood and H. Yuh and K. Zhurovich and S. Zweben and Bruce Lipschultz",

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doi = "10.1088/0029-5515/43/12/007",

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journal = "Nuclear Fusion",

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Marmar, ES, Bai, B, Boivin, RL, Bonoli, PT, Boswell, C, Bravenec, R, Carreras, B, Ernst, D, Fiore, C, Gangadhara, S, Gentle, K, Goetz, J, Granetz, R, Greenwald, M, Hallatschek, K, Hastie, J, Hosea, J, Hubbard, A, Hughes, JW, Hutchinson, I, In, Y, Irby, J, Jennings, T, Kopon, D, Kramer, G, LaBombard, B, Lee, WD, Lin, Y, Lipschultz, B, Liptac, J, Lynn, A, Marr, K, Maqueda, R, Melby, E, Mikkelsen, D, Mossessian, D, Nazikian, R, Nevins, WM, Parker, R, Pedersen, TS, Phillips, CK, Phillips, P, Pitcher, CS, Porkolab, M, Ramos, J, Redi, M, Rice, J, Rogers, BN, Rowan, WL, Sampsell, M, Schilling, G, Scott, S, Snipes, J, Snyder, P, Stotler, D, Taylor, G, Terry, JL, Wilson, H, Wilson, JR, Wolfe, SM, Wukitch, S, Xu, XQ, Youngblood, B, Yuh, H, Zhurovich, K, Zweben, S & Lipschultz, B 2003, 'Overview of recent alcator C-Mod research', Nuclear Fusion, vol. 43, no. 12, pp. 1610-1618. https://doi.org/10.1088/0029-5515/43/12/007

TY - JOUR

T1 - Overview of recent alcator C-Mod research

AU - Marmar, E.S.

AU - Bai, B.

AU - Boivin, R.L.

AU - Bonoli, P.T.

AU - Boswell, C.

AU - Bravenec, R.

AU - Carreras, B.

AU - Ernst, D.

AU - Fiore, C.

AU - Gangadhara, S.

AU - Gentle, K.

AU - Goetz, J.

AU - Granetz, R.

AU - Greenwald, M.

AU - Hallatschek, K.

AU - Hastie, J.

AU - Hosea, J.

AU - Hubbard, A.

AU - Hughes, J.W.

AU - Hutchinson, I.

AU - In, Y.

AU - Irby, J.

AU - Jennings, T.

AU - Kopon, D.

AU - Kramer, G.

AU - LaBombard, B.

AU - Lee, W.D.

AU - Lin, Y.

AU - Lipschultz, B.

AU - Liptac, J.

AU - Lynn, A.

AU - Marr, K.

AU - Maqueda, R.

AU - Melby, E.

AU - Mikkelsen, D.

AU - Mossessian, D.

AU - Nazikian, R.

AU - Nevins, W.M.

AU - Parker, R.

AU - Pedersen, T.S.

AU - Phillips, C.K.

AU - Phillips, P.

AU - Pitcher, C.S.

AU - Porkolab, M.

AU - Ramos, J.

AU - Redi, M.

AU - Rice, J.

AU - Rogers, B.N.

AU - Rowan, W.L.

AU - Sampsell, M.

AU - Schilling, G.

AU - Scott, S.

AU - Snipes, J.

AU - Snyder, P.

AU - Stotler, D.

AU - Taylor, G.

AU - Terry, J.L.

AU - Wilson, H.

AU - Wilson, J.R.

AU - Wolfe, S.M.

AU - Wukitch, S.

AU - Xu, X.Q.

AU - Youngblood, B.

AU - Yuh, H.

AU - Zhurovich, K.

AU - Zweben, S.

AU - Lipschultz, Bruce

PY - 2003/12/1

Y1 - 2003/12/1

N2 - Research on the Alcator C-Mod tokamak [1] is focused on high particle- and power-density plasma regimes to understand particle and energy transport in the core, the dynamics of the H-mode pedestal, and scrape-off layer and divertor physics. The auxiliary heating is provided exclusively by RF waves, and both the physics and technology of RF heating and current drive are studied. The momentum which is manifested in strong toroidal rotation, in the absence of direct momentum input, has been shown to be transported in from the edge of the plasma following the L-H transition, with timescale comparable to that for energy transport. In discharges which develop internal transport barriers, the rotation slows first inside the barrier region, and then subsequently outside of the barrier foot. Heat pulse propagation studies using sawteeth indicate a very narrow region of strongly reduced energy transport, located near r/a = 0.5. Addition of on-axis ICRF heating arrests the buildup of density and impurities, leading to quasi-steady conditions. The quasi-coherent mode associated with enhanced D-Alpha (EDA) H-mode appears to be due to a resistive ballooning instability. As the pedestal pressure gradient and temperature are increased in EDA H-mode, small ELMs appear; detailed modelling indicates that these are due to intermediate n peeling-ballooning modes. Phase contrast imaging has been used to directly detect density fluctuations driven by ICRF waves in the core of the plasma, and mode conversion to an intermediate wavelength ion cyclotron wave has been observed for the first time. The bursty turbulent density fluctuations, observed to drive rapid cross-field particle transport in the edge plasma, appear to play a key role in the dynamics of the density limit. Preparations for quasi-steady-state advanced tokamak studies with lower hybrid current drive are well underway, and time dependent modelling indicates that regimes with high bootstrap fraction can be produced.

AB - Research on the Alcator C-Mod tokamak [1] is focused on high particle- and power-density plasma regimes to understand particle and energy transport in the core, the dynamics of the H-mode pedestal, and scrape-off layer and divertor physics. The auxiliary heating is provided exclusively by RF waves, and both the physics and technology of RF heating and current drive are studied. The momentum which is manifested in strong toroidal rotation, in the absence of direct momentum input, has been shown to be transported in from the edge of the plasma following the L-H transition, with timescale comparable to that for energy transport. In discharges which develop internal transport barriers, the rotation slows first inside the barrier region, and then subsequently outside of the barrier foot. Heat pulse propagation studies using sawteeth indicate a very narrow region of strongly reduced energy transport, located near r/a = 0.5. Addition of on-axis ICRF heating arrests the buildup of density and impurities, leading to quasi-steady conditions. The quasi-coherent mode associated with enhanced D-Alpha (EDA) H-mode appears to be due to a resistive ballooning instability. As the pedestal pressure gradient and temperature are increased in EDA H-mode, small ELMs appear; detailed modelling indicates that these are due to intermediate n peeling-ballooning modes. Phase contrast imaging has been used to directly detect density fluctuations driven by ICRF waves in the core of the plasma, and mode conversion to an intermediate wavelength ion cyclotron wave has been observed for the first time. The bursty turbulent density fluctuations, observed to drive rapid cross-field particle transport in the edge plasma, appear to play a key role in the dynamics of the density limit. Preparations for quasi-steady-state advanced tokamak studies with lower hybrid current drive are well underway, and time dependent modelling indicates that regimes with high bootstrap fraction can be produced.

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U2 - 10.1088/0029-5515/43/12/007

DO - 10.1088/0029-5515/43/12/007

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SN - 0029-5515

VL - 43

SP - 1610

EP - 1618

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 12

ER -

Overview of recent alcator C-Mod research

Abstract

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