Plasma startup in the National Spherical Torus Experiment using transient coaxial helicity injection

Raman, R; Jarboe, T R; Nelson, B A; Mueller, D; Bell, M G; Ono, M; Kaita, R; LeBlanc, B; Menard, J; Paul, S; Roquemore, L; Bigelow, T; Maqueda, R

doi:10.1063/1.2515159

Title: Plasma startup in the National Spherical Torus Experiment using transient coaxial helicity injection

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Abstract

A method of plasma current generation known as coaxial helicity injection (CHI) has been successfully applied in the National Spherical Torus Experiment [M. Ono, S. M. Kaye, Y.-K. M. Peng et al., Nucl. Fusion 40, 3Y 557 (2000)] to form closed, nested magnetic surfaces carrying a plasma current up to 160 kA. In some discharges the generated current persists for surprisingly long, {approx}400 ms. While the CHI method has previously been studied in smaller experiments, such as the Helicity Injected Tokamak (HIT-II) [R. Raman, T. R. Jarboe, B. A. Nelson et al., Phys Rev. Lett. 90, 075005 (2003)] at the University of Washington, the significance of these results are (a) demonstration of the process in a vessel volume thirty times larger than HIT-II on a size scale more comparable to a reactor (b) a remarkable multiplication factor of 60 between the injected current and the achieved toroidal current, compared to six in previous experiments, and (c) for the first time, fast time scale visible imaging of the entire process that shows discharge formation, disconnection from the injector, and luminous structures consistent with the reconnection of magnetic field lines and closed flux surfaces. These significant results indicate favorable scaling with machinemore » size.« less

Authors:

Raman, R; Jarboe, T R; Nelson, B A ^[1]; Mueller, D; Bell, M G; Ono, M; Kaita, R; LeBlanc, B; Menard, J; Paul, S; Roquemore, L ^[2]; Bigelow, T ^[3]; Maqueda, R ^[4]

University of Washington, Seattle, Washington 98195 (United States)
Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)
Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
Nova Photonics, Princeton, New Jersey 08543 (United States)

Publication Date:: Tue May 15 00:00:00 EDT 2007

OSTI Identifier:: 20975045

Resource Type:: Journal Article

Journal Name:: Physics of Plasmas

Additional Journal Information:: Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2515159; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; EDUCATIONAL FACILITIES; ELECTRIC CURRENTS; MAGNETIC FIELDS; MAGNETIC RECONNECTION; MAGNETIC SURFACES; MULTIPLICATION FACTORS; PLASMA; PLASMA CONFINEMENT; PLASMA DIAGNOSTICS; SPHERICAL CONFIGURATION; TOKAMAK DEVICES; TRANSIENTS

Citation Formats


                    Raman, R, Jarboe, T R, Nelson, B A, Mueller, D, Bell, M G, Ono, M, Kaita, R, LeBlanc, B, Menard, J, Paul, S, Roquemore, L, Bigelow, T, and Maqueda, R. Plasma startup in the National Spherical Torus Experiment using transient coaxial helicity injection.  United States: N. p., 2007. 
        Web.  doi:10.1063/1.2515159.

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                    Raman, R, Jarboe, T R, Nelson, B A, Mueller, D, Bell, M G, Ono, M, Kaita, R, LeBlanc, B, Menard, J, Paul, S, Roquemore, L, Bigelow, T, & Maqueda, R. Plasma startup in the National Spherical Torus Experiment using transient coaxial helicity injection.  United States.  https://doi.org/10.1063/1.2515159

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                    Raman, R, Jarboe, T R, Nelson, B A, Mueller, D, Bell, M G, Ono, M, Kaita, R, LeBlanc, B, Menard, J, Paul, S, Roquemore, L, Bigelow, T, and Maqueda, R. 2007.  
        "Plasma startup in the National Spherical Torus Experiment using transient coaxial helicity injection".  United States.  https://doi.org/10.1063/1.2515159.

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@article{osti_20975045,

  title        = {Plasma startup in the National Spherical Torus Experiment using transient coaxial helicity injection},

  author       = {Raman, R and Jarboe, T R and Nelson, B A and Mueller, D and Bell, M G and Ono, M and Kaita, R and LeBlanc, B and Menard, J and Paul, S and Roquemore, L and Bigelow, T and Maqueda, R},

  abstractNote = {A method of plasma current generation known as coaxial helicity injection (CHI) has been successfully applied in the National Spherical Torus Experiment [M. Ono, S. M. Kaye, Y.-K. M. Peng et al., Nucl. Fusion 40, 3Y 557 (2000)] to form closed, nested magnetic surfaces carrying a plasma current up to 160 kA. In some discharges the generated current persists for surprisingly long, {approx}400 ms. While the CHI method has previously been studied in smaller experiments, such as the Helicity Injected Tokamak (HIT-II) [R. Raman, T. R. Jarboe, B. A. Nelson et al., Phys Rev. Lett. 90, 075005 (2003)] at the University of Washington, the significance of these results are (a) demonstration of the process in a vessel volume thirty times larger than HIT-II on a size scale more comparable to a reactor (b) a remarkable multiplication factor of 60 between the injected current and the achieved toroidal current, compared to six in previous experiments, and (c) for the first time, fast time scale visible imaging of the entire process that shows discharge formation, disconnection from the injector, and luminous structures consistent with the reconnection of magnetic field lines and closed flux surfaces. These significant results indicate favorable scaling with machine size.},

  doi          = {10.1063/1.2515159},

  url          = {https://www.osti.gov/biblio/20975045},
  journal      = {Physics of Plasmas},

  issn         = {1070-664X},

  number       = 5,

  volume       = 14,

  place        = {United States},

  year         = {Tue May 15 00:00:00 EDT 2007},

  month        = {Tue May 15 00:00:00 EDT 2007}

}

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