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8. Results of NSTX heating experiments

Author

Mueller, D., Ono, M., Bell, M.G., Bell, R.E., Bitter, M., Bourdelle, C., Darrow, D.S., Efthimion, P.C., Fredrickson, E.D., Gates, D.A., Goldston, R.J., Grisham, L.R., Hawryluk, R.J., Hill, K.W., Hosea, J.C., Jardin, S.C., Ji, H., Kaye, S.M., Kaita, R., Kugel, H.W., Johnson, D.W., LeBlanc, B.P., Majeski, R., Mazzucato, E., Medley, S.S., Menard, J.E., Park, H.K., Paul, S.F., Phillips, C.K., Redi, M.H., Rosenberg, A.L., Skinner, C.H., Soukhanovskii, V.A., Stratton, B., Synakowski, E.J., Taylor, G., Wilson, J.R., Zweben, S.J., Dorland, W.D., Peng, Y.K.M., Barry, R., Bigelow, T., Bush, C.E., Carter, M., Maingi, R., Menon, M., Ryan, P.M., Swain, D.W., Wilgen, J., Sabbagh, S.A., Paoletti, F., Bialek, J., Zhu, W., Raman, R., Jarboe, T.R., Nelson, B.A., Maqueda, R.J., Wurden, G.A., Pinsker, R.I., Schaffer, M., Ferron, J., Lao, L., Stutman, D., Finkenthal, M., Wampler, W., Kubota, S., Peebles, W.A., Gilmore, M., Mau, T.K., Lee, K.C., Domier, C.W., Deng, B.H., Johnson, M., Luhmann, N.C., Jr., Bonoli, P., Bers, A., Ram, A., Akers, R., Takase, Y., Ejiri, A., Ono, Y., Shiraiwa, S., Nishino, N., Mitarai, O., Nagata, M., Yang, J.G., Na, H., and Pacella, D.

Subjects
Fusion reactors, Business, Chemistry, Electronics, Electronics and electrical industries
Abstract

The National Spherical Torus Experiment (NSTX) at Princeton University, Princeton, NJ, is designed to assess the potential of the low-aspect-ratio spherical torus concept for magnetic plasma confinement. The plasma has been heated by up to 7 MW of neutral beam injection (NBI) at an injection energy of 100 keV and up to 6 MW of high harmonic fast wave (HHFW) at 30 MHz. NSTX has achieved [[beta].sub.T] of 32%. A variety of MHD phenomena have been observed to limit [beta]. NSTX has now begun addressing [T.sub.E] scaling, [beta] limits, and current drive issues. During the NBI heating experiments, a broad [T.sub.i] profile with [T.sub.i] up to 2 keV, [T.sub.i] > [T.sub.e] and a large toroidal rotation were observed. Transport analysis suggests that the impurity ions have diffusivities approaching neoclassical. For L-Mode plasmas, [T.sub.E] is up to two times the ITER97L H-Mode scaling and exceeds the ITER98pby2 H-Mode scaling in some cases. Transitions to H-Mode have been observed which result in an approximate doubling of [T.sub.E] after the transition in some conditions. During HHFW heating, [T.sub.e] > [T.sub.i] and [T.sub.e] up to 3.5 keV were observed. Current drive has been studied using both coaxial helicity injection with up to 390 kA of toroidal current and HHFW. HHFW has produced H-modes with significant bootstrap current fraction at low [I.sub.p], high q, and high [[beta].sub.p]. Index Terms--Fusion reactors, plasma confinement, tokamaks.

Published
2003

10. Characteristics of the First H-mode Discharges in NSTX

Author

Maingi, R., primary, Bell, M.G., additional, Bell, R.E., additional, Bush, C.E., additional, Fredrickson, E.D., additional, Gates, D.A., additional, Kaye, S.M., additional, Kugel, H.W., additional, LeBlanc, B.P., additional, Menard, J.E., additional, Mueller, D., additional, Sabbagh, S.A., additional, Stutman, D., additional, Taylor, G., additional, Johnson, D.W., additional, Kaita, R., additional, Maqueda, R.J., additional, Ono, M., additional, Paoletti, F., additional, Peng, Y-K.M., additional, Roquemore, A.L., additional, Skinner, C.H., additional, Soukhanovskii, V.A., additional, and and Synakowski, E.J., additional

Published
2001
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11. Images of edge turbulence in NSTX

Author

Zweben, S.J., Bush, C.E., Maqueda, R.J., Munsat, T., Stotler, D.P., Lowrance, J.L., Mastrocola, V.J., and Renda, G.

Subjects
Turbulence -- Research, Plasma physics -- Research, Business, Chemistry, Electronics, Electronics and electrical industries
Abstract

The two-dimensional structure of edge plasma turbulence has been measured in the National Spherical Torus Experiment (NSTX) by viewing the emission of the [D.sub.a] spectral line of deuterium. Images have been made at framing rates of up to 250 000 frames/s using an ultra-high speed charged coupled device camera developed by Princeton Scientific Instruments. A sequence of images showing the transition between L-mode and H-mode states is shown. Index Terms--Edge plasma, imaging, National Spherical Torus Experiment (NSTX), turbulence.

Published
2005

15. H-mode pedestal, ELM and power threshold studies in NSTX

Author

Maingi, R, primary, Bush, C.E, additional, Fredrickson, E.D, additional, Gates, D.A, additional, Kaye, S.M, additional, LeBlanc, B.P, additional, Menard, J.E, additional, Meyer, H, additional, Mueller, D, additional, Nishino, N, additional, Roquemore, A.L, additional, Sabbagh, S.A, additional, Tritz, K, additional, Zweben, S.J, additional, Bell, M.G, additional, Bell, R.E, additional, Biewer, T, additional, Boedo, J.A, additional, Johnson, D.W, additional, Kaita, R, additional, Kugel, H.W, additional, Maqueda, R.J, additional, Munsat, T, additional, Raman, R, additional, Soukhanovskii, V.A, additional, Stevenson, T, additional, and Stutman, D, additional

Published
2005
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16. High-speed imaging of edge turbulence in NSTX

Author

Zweben, S.J, primary, Maqueda, R.J, additional, Stotler, D.P, additional, Keesee, A, additional, Boedo, J, additional, Bush, C.E, additional, Kaye, S.M, additional, LeBlanc, B, additional, Lowrance, J.L, additional, Mastrocola, V.J, additional, Maingi, R, additional, Nishino, N, additional, Renda, G, additional, Swain, D.W, additional, Wilgen, J.B, additional, and Team, the NSTX, additional

Published
2003
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17. H-mode research in NSTX

Author

Maingi, R, primary, Bell, M.G, additional, Bell, R.E, additional, Bush, C.E, additional, Fredrickson, E.D, additional, Gates, D.A, additional, Gray, T, additional, Johnson, D.W, additional, Kaita, R, additional, Kaye, S.M, additional, Kubota, S, additional, Kugel, H.W, additional, Lasnier, C.J, additional, LeBlanc, B.P, additional, Maqueda, R.J, additional, Mastrovito, D, additional, Menard, J.E, additional, Mueller, D, additional, Ono, M, additional, Paoletti, F, additional, Paul, S.J, additional, Peng, Y.-K.M, additional, Roquemore, A.L, additional, Sabbagh, S.A, additional, Skinner, C.H, additional, Soukhanovskii, V.A, additional, Stutman, D, additional, Swain, D.W, additional, Synakowski, E.J, additional, Tan, T, additional, Wilgen, J.B, additional, and Zweben, S.J, additional

Published
2003
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18. -Limiting MHD instabilities in improved-performance NSTX spherical torus plasmas

Author

Menard, J.E, primary, Bell, M.G, additional, Bell, R.E, additional, Fredrickson, E.D, additional, Gates, D.A, additional, Kaye, S.M, additional, LeBlanc, B.P, additional, Maingi, R, additional, Mueller, D, additional, Sabbagh, S.A, additional, Stutman, D, additional, Bush, C.E, additional, Johnson, D.W, additional, Kaita, R, additional, Kugel, H.W, additional, Maqueda, R.J, additional, Paoletti, F, additional, Paul, S.F, additional, Ono, M, additional, Peng, Y.-K.M, additional, Skinner, C.H, additional, Synakowski, E.J, additional, and Team, the NSTX Research, additional

Published
2003
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19. Observations concerning the injection of a lithium aerosol into the edge of TFTR discharges

Author

Mansfield, D.K, primary, Johnson, D.W, additional, Grek, B, additional, Kugel, H.W, additional, Bell, M.G, additional, Bell, R.E, additional, Budny, R.V, additional, Bush, C.E, additional, Fredrickson, E.D, additional, Hill, K.W, additional, Jassby, D.L, additional, Maqueda, R.J, additional, Park, H.K, additional, Ramsey, A.T, additional, Synakowski, E.J, additional, Taylor, G, additional, and Wurden, G.A, additional

Published
2001
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20. Equilibrium properties of spherical torus plasmas in NSTX

Author

Sabbagh, S.A, primary, Kaye, S.M, additional, Menard, J, additional, Paoletti, F, additional, Bell, M, additional, Bell, R.E, additional, Bialek, J.M, additional, Bitter, M, additional, Fredrickson, E.D, additional, Gates, D.A, additional, Glasser, A.H, additional, Kugel, H, additional, Lao, L.L, additional, LeBlanc, B.P, additional, Maingi, R, additional, Maqueda, R.J, additional, Mazzucato, E, additional, Mueller, D, additional, Ono, M, additional, Paul, S.F, additional, Peng, M, additional, Skinner, C.H, additional, Stutman, D, additional, Wurden, G.A, additional, Zhu, W, additional, and Team, NSTX Research, additional

Published
2001
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21. Overview of recent Alcator C-Mod results

Author

Hutchinson, I.H., primary, Boivin, R., additional, Bonoli, P.T., additional, Boswell, C., additional, Bravenec, R., additional, Bretz, N.L., additional, Chatterjee, R., additional, Chung, T., additional, Eisner, E., additional, Fiore, C., additional, Gangadhara, S., additional, Gentle, K., additional, Goetz, J.A., additional, Granetz, R.S., additional, Greenwald, M.J., additional, Hosea, J.C., additional, Hubbard, A.E., additional, Hughes, J., additional, In, Y., additional, Irby, J., additional, LaBombard, B., additional, Lin, Y., additional, Lipschultz, B., additional, Maqueda, R.J., additional, Marmar, E.S., additional, Mazurenko, A., additional, Mikkelsen, D., additional, Mossessian, D., additional, Nachtrieb, R., additional, Nazikian, R., additional, Nelson-Melby, E., additional, Pappas, D., additional, Parker, R.R., additional, Pedersen, T. Sunn, additional, Phillips, P., additional, Pitcher, C.S., additional, Porkolab, M., additional, Rice, J.E., additional, Rowan, W., additional, Schilling, G., additional, Snipes, J.A., additional, Taylor, G., additional, Terry, J.L., additional, Wilson, J.R., additional, Wolfe, S.M., additional, Wukitch, S.J., additional, Yuh, H., additional, Zweben, S.J., additional, Acedo, P., additional, Brambilla, M., additional, Carreras, B.A., additional, Gandy, R., additional, Hallock, G.A., additional, Dorland, W., additional, Johnson, D., additional, Krashennikova, N., additional, Phillips, C., additional, Tutt, T., additional, Watts, C., additional, and Umansky, M., additional

Published
2001
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22. Ohmic flux consumption during initial operation of the NSTX spherical torus

Author

Menard, J.E, primary, LeBlanc, B.P, additional, Sabbagh, S.A, additional, Bell, M.G, additional, Bell, R.E, additional, Fredrickson, E.D, additional, Gates, D.A, additional, Jardin, S.C, additional, Johnson, D.W, additional, Kaye, S.M, additional, Kugel, H.W, additional, Maingi, R, additional, Maqueda, R.J, additional, Mueller, D, additional, Ono, M, additional, Paoletti, F, additional, Paul, S.F, additional, Skinner, C.H, additional, Stutman, D, additional, and Team, NSTX Research, additional

Published
2001
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26. FRX-L: A field-reversed configuration plasma injector for magnetized target fusion.

Author

Taccetti, J.M., Intrator, T.P., Wurden, G.A., Zhang, S.Y., Aragonez, R., Assmus, P.N., Bass, C.M., Carey, C., deVries, S.A., Fienup, W.J., Furno, I., Hsu, S.C., Kozar, M.P., Langner, M.C., Liang, J., Maqueda, R.J., Martinez, R.A., Sanchez, P.G., Schoenberg, K.F., and Scott, K.J.

Subjects
PLASMA gases, FUSION (Phase transformation), MAGNETIC fields, SCIENTIFIC apparatus & instruments
Abstract

We describe the experiment and technology leading to a target plasma for the magnetized target fusion research effort, an approach to fusion wherein a plasma with embedded magnetic fields is formed and subsequently adiabatically compressed to fusion conditions. The target plasmas under consideration, field-reversed configurations (FRCs), have the required closed-field-line topology and are translatable and compressible. Our goal is to form high-density (10[sup 17] cm[sup -3]) FRCs on the field-reversed experiment-liner (FRX-L) device, inside a 36 cm long, 6.2 cm radius theta coil, with 5 T peak magnetic field and an azimuthal electric field as high as 1 kV/cm. FRCs have been formed with an equilibrium density n[sub e]≈(1 to 2)×10[sup 16] cm[sup -3], T[sub e]+T[sub i]≈250 eV, and excluded flux ≈2 to 3 mWb. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
2003
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27. The new infrared imaging system on Alcator C-Mod.

Author

Maqueda, R.J., Wurden, G.A., Terry, J.L., and Stillerman, J.A.

Subjects
*IMAGING systems, *INFRARED equipment, *TOKAMAKS
Abstract

Describes the installation of an infrared imaging system on the Alcator C-Mod tokamak. Design and components of the system; System's use of an Amber Radiance 1 IR video camera to view a region of the lower divertor; Capture of the standard video frames; Considerable heating below the outer divertor's nose.

Published
1999
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28. High-speed imaging of edge turbulence in NSTX

Author

Zweben, S.J., Maqueda, R.J., Stotler, D.P., Keesee, A., Boedo, J., Bush, C.E., Kaye, S.M., LeBlanc, B., Lowrance, J.L., Mastrocola, V.J., Maingi, R., Nishino, N., Renda, G., Swain, D.W., Wilgen, J.B., and Team, the NSTX

Abstract

The two-dimensional radial vs poloidal structure and motion of edge turbulence in the National Spherical Torus Experiment (NSTX) were measured using high-speed imaging of the visible light emission from a localized neutral gas puff. Edge turbulence images are shown and analysed for Ohmic, L- and H-mode plasma conditions. The two-dimensional images often show regions of strong localized light emission known as ‘blobs’, which move both poloidally and radially at a typical speed of ≈105 cm s−1, and sometimes show spatially periodic features.

Published
2004

29. <iopmath latex="${\beta}$">β</iopmath>-Limiting MHD instabilities in improved-performance NSTX spherical torus plasmas

Author

Menard, J.E., Bell, M.G., Bell, R.E., Fredrickson, E.D., Gates, D.A., Kaye, S.M., LeBlanc, B.P., Maingi, R., Mueller, D., Sabbagh, S.A., Stutman, D., Bush, C.E., Johnson, D.W., Kaita, R., Kugel, H.W., Maqueda, R.J., Paoletti, F., Paul, S.F, Ono, M., Peng, Y.-K.M., Skinner, C.H., Synakowski, E.J., and Team, the NSTX Research

Abstract

Global magnetohydrodynamic (MHD) stability limits in the National Spherical Torus Experiment (NSTX) have increased significantly recently due to a combination of device and operational improvements. First, more routine H-mode operation with broadened pressure profiles allows access to higher normalized β and lower internal inductance. Second, the correction of a poloidal field coil induced error-field has largely eliminated locked tearing modes during normal operation and increased the maximum achievable β. As a result of these improvements, peak β values have reached (not simultaneously) βT&equal;35&percent;, βN&equal;6.4, &langle;βN&rangle;&equal;4.5, βN/li&equal;10, and βP&equal;1.4. High βP operation with reduced tearing activity has allowed a doubling of discharge pulse-length to just over 1 s with sustained periods of βN&approx;6 above the ideal no-wall limit and near the with-wall limit. Details of the β-limit scalings and β-limiting instabilities in various operating regimes are described.

Published
2003

30. High performance plasmas on the National Spherical Torus Experiment

Author

Gates, D.A., primary, Bell, M.G., additional, Bell, R.E., additional, Bialek, J., additional, Bigelow, T., additional, Bitter, M., additional, Bonoli, P., additional, Darrow, D., additional, Efthimion, P., additional, Ferron, J., additional, Fredrickson, E., additional, Grisham, L., additional, Hosea, J., additional, Johnson, D., additional, Kaita, R., additional, Kaye, S., additional, Kubota, S., additional, Kugel, H., additional, LeBlanc, B., additional, Maingi, R., additional, Manickam, J., additional, Mau, T.K., additional, Maqueda, R.J., additional, Mazzucato, E., additional, Menard, J., additional, Mueller, D., additional, Nelson, B., additional, Nishino, N., additional, Ono, M., additional, Paoletti, F., additional, Paul, S., additional, Peng, Y.-K.M., additional, Phillips, C.K., additional, Raman, R., additional, Ryan, P., additional, Sabbagh, S.A., additional, Schaffer, M., additional, Skinner, C.H., additional, Stutman, D., additional, Swain, D., additional, Synakowski, E., additional, Takase, Y., additional, Wilgen, J., additional, Wilson, J.R., additional, Zhu, W., additional, Zweben, S., additional, Bers, A., additional, Carter, M., additional, Deng, B., additional, Domier, C., additional, Doyle, E., additional, Finkenthal, M., additional, Hill, K., additional, Jarboe, T., additional, Jardin, S., additional, Ji, H., additional, Lao, L., additional, Lee, K.C., additional, Luhmann, N., additional, Majeski, R., additional, Park, H., additional, Peebles, T., additional, Pinsker, R.I., additional, Porter, G., additional, Ram, A., additional, Rensink, M., additional, Rognlien, T., additional, Stotler, D., additional, Stratton, B., additional, Taylor, G., additional, Wampler, W., additional, Wurden, G.A., additional, Xu, X.Q., additional, and Zeng, L., additional

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