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Title: Overview of NSTX Upgrade initial results and modelling highlights

Abstract

The National Spherical Torus Experiment (NSTX) has undergone a major upgrade, and the NSTX Upgrade (NSTX-U) Project was completed in the summer of 2015. NSTX-U first plasma was subsequently achieved, diagnostic and control systems have been commissioned, the H-mode accessed, magnetic error fields identified and mitigated, and the first physics research campaign carried out. During ten run weeks of operation, NSTX-U surpassed NSTX record pulse-durations and toroidal fields (TF), and high-performance ~1 MA H-mode plasmas comparable to the best of NSTX have been sustained near and slightly above the n = 1 no-wall stability limit and with H-mode confinement multiplier H 98y,2 above 1. Transport and turbulence studies in L-mode plasmas have identified the coexistence of at least two ion-gyro-scale turbulent micro-instabilities near the same radial location but propagating in opposite (i.e. ion and electron diamagnetic) directions. These modes have the characteristics of ion-temperature gradient and micro-tearing modes, respectively, and the role of these modes in contributing to thermal transport is under active investigation. The new second more tangential neutral beam injection was observed to significantly modify the stability of two types of Alfven eigenmodes. Improvements in offline disruption forecasting were made in the areas of identification of rotating MHDmore » modes and other macroscopic instabilities using the disruption event characterization and forecasting code. Finally, the materials analysis and particle probe was utilized on NSTX-U for the first time and enabled assessments of the correlation between boronized wall conditions and plasma performance. These and other highlights from the first run campaign of NSTX-U are described.« less

Authors:
ORCiD logo [1];  [2]; ORCiD logo [1];  [2]; ORCiD logo [1]; ORCiD logo [1];  [3]; ORCiD logo [1];  [4]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [1];  [5]; ORCiD logo [1];  [1]; ORCiD logo [1];  [6]; ORCiD logo [1];  [1] more »;  [5];  [4]; ORCiD logo [1]; ORCiD logo [6]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [1]; ORCiD logo [1]; ORCiD logo [1];  [7];  [8]; ORCiD logo [1];  [3];  [5];  [9];  [10];  [1];  [5];  [9]; ORCiD logo [1];  [10];  [1];  [5];  [8];  [1];  [11];  [9]; ORCiD logo [1]; ORCiD logo [1];  [12];  [13]; ORCiD logo [14];  [13];  [8]; ORCiD logo [1];  [1]; ORCiD logo [1];  [11];  [1];  [13];  [13];  [15];  [5];  [16]; ORCiD logo [1];  [5];  [8];  [1];  [13];  [7]; ORCiD logo [1];  [1]; ORCiD logo [12]; ORCiD logo [12]; ORCiD logo [1];  [13];  [10];  [11]; ORCiD logo [1];  [17];  [5];  [18];  [19]; ORCiD logo [1]; ORCiD logo [1];  [4];  [20]; ORCiD logo [12];  [19];  [21];  [1];  [15]; ORCiD logo [1];  [15];  [1];  [16]; ORCiD logo [1] « less
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. Univ. of Illinois, Urbana-Champaign, IL (United States)
  3. Columbia Univ., New York, NY (United States)
  4. Univ. of California, Los Angeles, CA (United States)
  5. Univ. of Wisconsin, Madison, WI (United States)
  6. Univ. of California, Irvine, CA (United States)
  7. Univ. of Washington, Seattle, WA (United States)
  8. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  9. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  10. Nova Photonics, Princeton, NJ (United States)
  11. Univ. of California, Davis, CA (United States)
  12. Princeton Univ., NJ (United States)
  13. General Atomics, San Diego, CA (United States)
  14. The College of New Jersey, Ewing, NJ (United States)
  15. Johns Hopkins Univ., Baltimore, MD (United States)
  16. Univ. of Tennessee, Knoxville, TN (United States)
  17. X Science LLC, Plainsboro, NJ (United States)
  18. College of William and Mary, Williamsburg, VA (United States)
  19. Lodestar Research Corporation, Boulder, CO (United States)
  20. Univ. of Michigan, Ann Arbor, MI (United States)
  21. Lehigh Univ., Bethlehem, PA (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
1367916
Grant/Contract Number:
AC02-09CH11466
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 57; Journal Issue: 10; Related Information: Please use this identifier to cite or link to this item: http://arks.princeton.edu/ark:/88435/dsp016w924f316; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; NSTX-U; Spherical tokamak; Alfven Eigenmodes

Citation Formats

Menard, J. E., Allain, J. P., Battaglia, D. J., Bedoya, F., Bell, R. E., Belova, E., Berkery, J. W., Boyer, M. D., Crocker, N., Diallo, A., Ebrahimi, F., Ferraro, N., Fredrickson, E., Frerichs, H., Gerhardt, S., Gorelenkov, N., Guttenfelder, W., Heidbrink, W., Kaita, R., Kaye, S. M., Kriete, D. M., Kubota, S., LeBlanc, B. P., Liu, D., Lunsford, R., Mueller, D., Myers, C. E., Ono, M., Park, J. -K., Podesta, M., Raman, R., Reinke, M., Ren, Y., Sabbagh, S. A., Schmitz, O., Scotti, F., Sechrest, Y., Skinner, C. H., Smith, D. R., Soukhanovskii, V., Stoltzfus-Dueck, T., Yuh, H., Wang, Z., Waters, I., Ahn, J. -W., Andre, R., Barchfeld, R., Beiersdorfer, P., Bertelli, N., Bhattacharjee, A., Brennan, D., Buttery, R., Capece, A., Canal, G., Canik, J., Chang, C. S., Darrow, D., Delgado-Aparicio, L., Domier, C., Ethier, S., Evans, T., Ferron, J., Finkenthal, M., Fonck, R., Gan, K., Gates, D., Goumiri, I., Gray, T., Hosea, J., Humphreys, D., Jarboe, T., Jardin, S., Jaworski, M. A., Koel, B., Kolemen, E., Ku, S., La Haye, R. J., Levinton, F., Luhmann, N., Maingi, R., Maqueda, R., McKee, G., Meier, E., Myra, J., Perkins, R., Poli, F., Rhodes, T., Riquezes, J., Rowley, C., Russell, D., Schuster, E., Stratton, B., Stutman, D., Taylor, G., Tritz, K., Wang, W., Wirth, B., and Zweben, S. J.. Overview of NSTX Upgrade initial results and modelling highlights. United States: N. p., 2017. Web. doi:10.1088/1741-4326/aa600a.
Menard, J. E., Allain, J. P., Battaglia, D. J., Bedoya, F., Bell, R. E., Belova, E., Berkery, J. W., Boyer, M. D., Crocker, N., Diallo, A., Ebrahimi, F., Ferraro, N., Fredrickson, E., Frerichs, H., Gerhardt, S., Gorelenkov, N., Guttenfelder, W., Heidbrink, W., Kaita, R., Kaye, S. M., Kriete, D. M., Kubota, S., LeBlanc, B. P., Liu, D., Lunsford, R., Mueller, D., Myers, C. E., Ono, M., Park, J. -K., Podesta, M., Raman, R., Reinke, M., Ren, Y., Sabbagh, S. A., Schmitz, O., Scotti, F., Sechrest, Y., Skinner, C. H., Smith, D. R., Soukhanovskii, V., Stoltzfus-Dueck, T., Yuh, H., Wang, Z., Waters, I., Ahn, J. -W., Andre, R., Barchfeld, R., Beiersdorfer, P., Bertelli, N., Bhattacharjee, A., Brennan, D., Buttery, R., Capece, A., Canal, G., Canik, J., Chang, C. S., Darrow, D., Delgado-Aparicio, L., Domier, C., Ethier, S., Evans, T., Ferron, J., Finkenthal, M., Fonck, R., Gan, K., Gates, D., Goumiri, I., Gray, T., Hosea, J., Humphreys, D., Jarboe, T., Jardin, S., Jaworski, M. A., Koel, B., Kolemen, E., Ku, S., La Haye, R. J., Levinton, F., Luhmann, N., Maingi, R., Maqueda, R., McKee, G., Meier, E., Myra, J., Perkins, R., Poli, F., Rhodes, T., Riquezes, J., Rowley, C., Russell, D., Schuster, E., Stratton, B., Stutman, D., Taylor, G., Tritz, K., Wang, W., Wirth, B., & Zweben, S. J.. Overview of NSTX Upgrade initial results and modelling highlights. United States. doi:10.1088/1741-4326/aa600a.
Menard, J. E., Allain, J. P., Battaglia, D. J., Bedoya, F., Bell, R. E., Belova, E., Berkery, J. W., Boyer, M. D., Crocker, N., Diallo, A., Ebrahimi, F., Ferraro, N., Fredrickson, E., Frerichs, H., Gerhardt, S., Gorelenkov, N., Guttenfelder, W., Heidbrink, W., Kaita, R., Kaye, S. M., Kriete, D. M., Kubota, S., LeBlanc, B. P., Liu, D., Lunsford, R., Mueller, D., Myers, C. E., Ono, M., Park, J. -K., Podesta, M., Raman, R., Reinke, M., Ren, Y., Sabbagh, S. A., Schmitz, O., Scotti, F., Sechrest, Y., Skinner, C. H., Smith, D. R., Soukhanovskii, V., Stoltzfus-Dueck, T., Yuh, H., Wang, Z., Waters, I., Ahn, J. -W., Andre, R., Barchfeld, R., Beiersdorfer, P., Bertelli, N., Bhattacharjee, A., Brennan, D., Buttery, R., Capece, A., Canal, G., Canik, J., Chang, C. S., Darrow, D., Delgado-Aparicio, L., Domier, C., Ethier, S., Evans, T., Ferron, J., Finkenthal, M., Fonck, R., Gan, K., Gates, D., Goumiri, I., Gray, T., Hosea, J., Humphreys, D., Jarboe, T., Jardin, S., Jaworski, M. A., Koel, B., Kolemen, E., Ku, S., La Haye, R. J., Levinton, F., Luhmann, N., Maingi, R., Maqueda, R., McKee, G., Meier, E., Myra, J., Perkins, R., Poli, F., Rhodes, T., Riquezes, J., Rowley, C., Russell, D., Schuster, E., Stratton, B., Stutman, D., Taylor, G., Tritz, K., Wang, W., Wirth, B., and Zweben, S. J.. Tue . "Overview of NSTX Upgrade initial results and modelling highlights". United States. doi:10.1088/1741-4326/aa600a.
@article{osti_1367916,
title = {Overview of NSTX Upgrade initial results and modelling highlights},
author = {Menard, J. E. and Allain, J. P. and Battaglia, D. J. and Bedoya, F. and Bell, R. E. and Belova, E. and Berkery, J. W. and Boyer, M. D. and Crocker, N. and Diallo, A. and Ebrahimi, F. and Ferraro, N. and Fredrickson, E. and Frerichs, H. and Gerhardt, S. and Gorelenkov, N. and Guttenfelder, W. and Heidbrink, W. and Kaita, R. and Kaye, S. M. and Kriete, D. M. and Kubota, S. and LeBlanc, B. P. and Liu, D. and Lunsford, R. and Mueller, D. and Myers, C. E. and Ono, M. and Park, J. -K. and Podesta, M. and Raman, R. and Reinke, M. and Ren, Y. and Sabbagh, S. A. and Schmitz, O. and Scotti, F. and Sechrest, Y. and Skinner, C. H. and Smith, D. R. and Soukhanovskii, V. and Stoltzfus-Dueck, T. and Yuh, H. and Wang, Z. and Waters, I. and Ahn, J. -W. and Andre, R. and Barchfeld, R. and Beiersdorfer, P. and Bertelli, N. and Bhattacharjee, A. and Brennan, D. and Buttery, R. and Capece, A. and Canal, G. and Canik, J. and Chang, C. S. and Darrow, D. and Delgado-Aparicio, L. and Domier, C. and Ethier, S. and Evans, T. and Ferron, J. and Finkenthal, M. and Fonck, R. and Gan, K. and Gates, D. and Goumiri, I. and Gray, T. and Hosea, J. and Humphreys, D. and Jarboe, T. and Jardin, S. and Jaworski, M. A. and Koel, B. and Kolemen, E. and Ku, S. and La Haye, R. J. and Levinton, F. and Luhmann, N. and Maingi, R. and Maqueda, R. and McKee, G. and Meier, E. and Myra, J. and Perkins, R. and Poli, F. and Rhodes, T. and Riquezes, J. and Rowley, C. and Russell, D. and Schuster, E. and Stratton, B. and Stutman, D. and Taylor, G. and Tritz, K. and Wang, W. and Wirth, B. and Zweben, S. J.},
abstractNote = {The National Spherical Torus Experiment (NSTX) has undergone a major upgrade, and the NSTX Upgrade (NSTX-U) Project was completed in the summer of 2015. NSTX-U first plasma was subsequently achieved, diagnostic and control systems have been commissioned, the H-mode accessed, magnetic error fields identified and mitigated, and the first physics research campaign carried out. During ten run weeks of operation, NSTX-U surpassed NSTX record pulse-durations and toroidal fields (TF), and high-performance ~1 MA H-mode plasmas comparable to the best of NSTX have been sustained near and slightly above the n = 1 no-wall stability limit and with H-mode confinement multiplier H98y,2 above 1. Transport and turbulence studies in L-mode plasmas have identified the coexistence of at least two ion-gyro-scale turbulent micro-instabilities near the same radial location but propagating in opposite (i.e. ion and electron diamagnetic) directions. These modes have the characteristics of ion-temperature gradient and micro-tearing modes, respectively, and the role of these modes in contributing to thermal transport is under active investigation. The new second more tangential neutral beam injection was observed to significantly modify the stability of two types of Alfven eigenmodes. Improvements in offline disruption forecasting were made in the areas of identification of rotating MHD modes and other macroscopic instabilities using the disruption event characterization and forecasting code. Finally, the materials analysis and particle probe was utilized on NSTX-U for the first time and enabled assessments of the correlation between boronized wall conditions and plasma performance. These and other highlights from the first run campaign of NSTX-U are described.},
doi = {10.1088/1741-4326/aa600a},
journal = {Nuclear Fusion},
number = 10,
volume = 57,
place = {United States},
year = {Tue Jun 20 00:00:00 EDT 2017},
month = {Tue Jun 20 00:00:00 EDT 2017}
}

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  • The National Spherical Torus Experiment (NSTX) has undergone a major upgrade, and the NSTX Upgrade (NSTX-U) Project was completed in the summer of 2015. NSTX-U first plasma was subsequently achieved, diagnostic and control systems have been commissioned, H-Mode accessed, magnetic error fields identified and mitigated, and the first physics research campaign carried out. During 10 run weeks of operation, NSTX-U surpassed NSTX-record pulse-durations and toroidal fields, and high-performance ~1MA H-mode plasmas comparable to the best of NSTX have been sustained near and slightly above the n=1 no-wall stability limit and with H-mode confinement multiplier H98y2 above 1. Transport and turbulencemore » studies in L-mode plasmas have identified the coexistence of at least two ion-gyro-scale turbulent micro-instabilities near the same radial location but propagating in opposite (i.e. ion and electron diamagnetic) directions. These modes have the characteristics of ion-temperature gradient and micro-tearing modes, respectively, and the role of these modes in contributing to thermal transport is under active investigation. The new second more tangential neutral beam injection was observed to significantly modify the stability of two types of Alfven Eigenmodes. Improvements in offline disruption forecasting were made in the areas of identification of rotating MHD modes and other macroscopic instabilities using the Disruption Event Characterization and Forecasting (DECAF) code. Lastly, the Materials Analysis and Particle Probe (MAPP) was utilized on NSTX-U for the first time and enabled assessments of the correlation between boronized wall conditions and plasma performance. These and other highlights from the first run campaign of NSTX-U are described.« less
  • Polarimetry is a powerful diagnostic technique to probe plasma equilibria and magnetic fluctuations in fusion plasmas. In a high beta plasma such as the National Spherical Torus eXperiment (NSTX), these measurements are important to understand plasma stability and anomalous transport. A 288 GHz polarimeter operating along a major radial chord in retroreflection geometry has been developed and is being tested on the DIII-D tokamak to prepare for future implementation on NSTX-Upgrade. The system launches a rotating linearly polarized beam and detects the phase shift directly related to the polarization change caused by the plasma. To accomplish this, a pair ofmore » orthogonal linearly polarized beams with a stable difference frequency is generated using a single sideband modulation technique, then combined and transformed to be counter-rotating circularly polarized. To improve phase resolution, quasi-optical isolation, using Faraday rotators and polarizers, is utilized to eliminate a multi-path feedback effect, which is found to be the primary source of phase error. The bench tests in the laboratory and DIII-D power supply test discharges indicate {<=}1 Degree-Sign phase resolution.« less
  • A real-time velocity (RTV) diagnostic based on active charge-exchange recombination spectroscopy is now operational on the National Spherical Torus Experiment-Upgrade (NSTX-U) spherical torus (Menard et al 2012 Nucl. Fusion 52 083015). We designed the system in order to supply plasma velocity data in real time to the NSTX-U plasma control system, as required for the implementation of toroidal rotation control. Our measurements are available from four radii at a maximum sampling frequency of 5 kHz. Post-discharge analysis of RTV data provides additional information on ion temperature, toroidal velocity and density of carbon impurities. Furthermore, examples of physics studies enabled bymore » RTV measurements from initial operations of NSTX-U are discussed.« less
  • The spherical tokamak (ST) is a leading candidate for a Fusion Nuclear Science Facility (FNSF) due to its compact size and modular configuration. The National Spherical Torus eXperiment (NSTX) is a MA-class ST facility in the US actively developing the physics basis for an ST-based FNSF. In plasma transport research, ST experiments exhibit a strong (nearly inverse) scaling of normalized confinement with collisionality, and if this trend holds at low collisionality, high fusion neutron fluences could be achievable in very compact ST devices. A major motivation for the NSTX Upgrade (NSTX-U) is to span the next factor of 3-6 reductionmore » in collisionality. To achieve this collisionality reduction with equilibrated profiles, NSTX-U will double the toroidal field, plasma current, and NBI heating power and increase the pulse length from 1-1.5 s to 5-8 s. In the area of stability and advanced scenarios, plasmas with higher aspect ratio and elongation, high beta(N), and broad current profiles approaching those of an ST-based FNSF have been produced in NSTX using active control of the plasma beta and advanced resistive wall mode control. High non-inductive current fractions of 70% have been sustained for many current diffusion times, and the more tangential injection of the 2nd NBI of the Upgrade is projected to increase the NBI current drive by up to a factor of 2 and support 100% non-inductive operation. More tangential NBI injection is also projected to provide non-solenoidal current ramp-up as needed for an ST-based FNSF. In boundary physics, NSTX measures an inverse relationship between the scrape-off layer heat-flux width and plasma current that could unfavourably impact next-step devices. Recently, NSTX has successfully demonstrated substantial heat-flux reduction using a snowflake divertor configuration, and this type of divertor is incorporated in the NSTX-U design. The physics and engineering design supporting NSTX Upgrade is described.« less