Experiments in DIII-D toward achieving rapid shutdown with runaway electron suppression

E. M. Hollmann; N. Commaux; N. W. Eidietis; T. E. Evans; D. A. Humphreys; A. N. James; T. C. Jernigan; P. B. Parks; E. J. Strait; J. C. Wesley; J. H. Yu; M. E. Austin; L. R. Baylor; N. H. Brooks; V. A. Izzo; G. L. Jackson; M. A. Van Zeeland; W. Wu

doi:10.1063/1.3309426

Experiments in DIII-D toward achieving rapid shutdown with runaway electron suppression

E. M. Hollmann, N. Commaux, N. W. Eidietis, T. E. Evans, D. A. Humphreys, A. N. James, T. C. Jernigan, P. B. Parks, E. J. Strait, J. C. Wesley, J. H. Yu, M. E. Austin, L. R. Baylor, N. H. Brooks, V. A. Izzo, G. L. Jackson, M. A. Van Zeeland, W. Wu

Fusion Energy Division

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66 Scopus citations

Abstract

Experiments have been performed in the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] toward understanding runaway electron formation and amplification during rapid discharge shutdown, as well as toward achieving complete collisional suppression of these runaway electrons via massive delivery of impurities. Runaway acceleration and amplification appear to be well explained using the zero-dimensional (0D) current quench toroidal electric field. 0D or even one-dimensional modeling using a Dreicer seed term, however, appears to be too small to explain the initial runaway seed formation. Up to 15% of the line-average electron density required for complete runaway suppression has been achieved in the middle of the current quench using optimized massive gas injection with multiple small gas valves firing simultaneously. The novel rapid shutdown techniques of massive shattered pellet injection and shell pellet injection have been demonstrated for the first time. Experiments using external magnetic perturbations to deconfine runaways have shown promising preliminary results.

Original language	English
Article number	056117
Journal	Physics of Plasmas
Volume	17
Issue number	5
DOIs	https://doi.org/10.1063/1.3309426
State	Published - May 2010

Funding

The technical assistance of the DIII-D staff, especially B. Williams with the large shell pellet injector, D. Sundstrom with the small shell pellet injector, and J. Kulchar with diagnostics, is gratefully acknowledged. This work supported in part by the U.S. Department of Energy under Contract Nos. DE-FG02-07ER54917, DE-FG02-05ER54809, DE-AC05-00OR22725, DE-FC02-04ER54698, DE-FG02-95ER54309, and DE-FG03-97ER54415.

Funders	Funder number
U.S. Department of Energy	DE-AC05-00OR22725, DE-FG03-97ER54415, DE-FG02-05ER54809, DE-FC02-04ER54698, DE-FG02-07ER54917, DE-FG02-95ER54309

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1063/1.3309426

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Hollmann, E. M., Commaux, N., Eidietis, N. W., Evans, T. E., Humphreys, D. A., James, A. N., Jernigan, T. C., Parks, P. B., Strait, E. J., Wesley, J. C., Yu, J. H., Austin, M. E., Baylor, L. R., Brooks, N. H., Izzo, V. A., Jackson, G. L., Van Zeeland, M. A., & Wu, W. (2010). Experiments in DIII-D toward achieving rapid shutdown with runaway electron suppression. Physics of Plasmas, 17(5), Article 056117. https://doi.org/10.1063/1.3309426

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title = "Experiments in DIII-D toward achieving rapid shutdown with runaway electron suppression",

abstract = "Experiments have been performed in the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] toward understanding runaway electron formation and amplification during rapid discharge shutdown, as well as toward achieving complete collisional suppression of these runaway electrons via massive delivery of impurities. Runaway acceleration and amplification appear to be well explained using the zero-dimensional (0D) current quench toroidal electric field. 0D or even one-dimensional modeling using a Dreicer seed term, however, appears to be too small to explain the initial runaway seed formation. Up to 15% of the line-average electron density required for complete runaway suppression has been achieved in the middle of the current quench using optimized massive gas injection with multiple small gas valves firing simultaneously. The novel rapid shutdown techniques of massive shattered pellet injection and shell pellet injection have been demonstrated for the first time. Experiments using external magnetic perturbations to deconfine runaways have shown promising preliminary results.",

author = "Hollmann, {E. M.} and N. Commaux and Eidietis, {N. W.} and Evans, {T. E.} and Humphreys, {D. A.} and James, {A. N.} and Jernigan, {T. C.} and Parks, {P. B.} and Strait, {E. J.} and Wesley, {J. C.} and Yu, {J. H.} and Austin, {M. E.} and Baylor, {L. R.} and Brooks, {N. H.} and Izzo, {V. A.} and Jackson, {G. L.} and {Van Zeeland}, {M. A.} and W. Wu",

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doi = "10.1063/1.3309426",

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Hollmann, EM, Commaux, N, Eidietis, NW, Evans, TE, Humphreys, DA, James, AN, Jernigan, TC, Parks, PB, Strait, EJ, Wesley, JC, Yu, JH, Austin, ME, Baylor, LR, Brooks, NH, Izzo, VA, Jackson, GL, Van Zeeland, MA & Wu, W 2010, 'Experiments in DIII-D toward achieving rapid shutdown with runaway electron suppression', Physics of Plasmas, vol. 17, no. 5, 056117. https://doi.org/10.1063/1.3309426

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AU - Hollmann, E. M.

AU - Commaux, N.

AU - Eidietis, N. W.

AU - Evans, T. E.

AU - Humphreys, D. A.

AU - James, A. N.

AU - Jernigan, T. C.

AU - Parks, P. B.

AU - Strait, E. J.

AU - Wesley, J. C.

AU - Yu, J. H.

AU - Austin, M. E.

AU - Baylor, L. R.

AU - Brooks, N. H.

AU - Izzo, V. A.

AU - Jackson, G. L.

AU - Van Zeeland, M. A.

AU - Wu, W.

PY - 2010/5

Y1 - 2010/5

N2 - Experiments have been performed in the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] toward understanding runaway electron formation and amplification during rapid discharge shutdown, as well as toward achieving complete collisional suppression of these runaway electrons via massive delivery of impurities. Runaway acceleration and amplification appear to be well explained using the zero-dimensional (0D) current quench toroidal electric field. 0D or even one-dimensional modeling using a Dreicer seed term, however, appears to be too small to explain the initial runaway seed formation. Up to 15% of the line-average electron density required for complete runaway suppression has been achieved in the middle of the current quench using optimized massive gas injection with multiple small gas valves firing simultaneously. The novel rapid shutdown techniques of massive shattered pellet injection and shell pellet injection have been demonstrated for the first time. Experiments using external magnetic perturbations to deconfine runaways have shown promising preliminary results.

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Experiments in DIII-D toward achieving rapid shutdown with runaway electron suppression

Abstract

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UN SDGs

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