Study of argon assimilation into the post-disruption runaway electron plateau in DIII-D and comparison with a 1D diffusion model

E. M. Hollmann; N. W. Eidietis; J. L. Herfindal; P. B. Parks; A. Y. Pigarov; D. Shiraki; M. E. Austin; L. Bardoczi; L. Baylor; I. Bykov; T. N. Carlstrom; D. Kaplan; C. J. Lasnier; A. Lvovskiy; A. Moser; R. A. Moyer; C. Paz-Soldan; D. L. Rudakov; C. Samuell; M. Shafer; M. Van Zeeland; A. Welander; R. Wilcox

doi:10.1088/1741-4326/ab32b2

Study of argon assimilation into the post-disruption runaway electron plateau in DIII-D and comparison with a 1D diffusion model

E. M. Hollmann, N. W. Eidietis, J. L. Herfindal, P. B. Parks, A. Y. Pigarov, D. Shiraki, M. E. Austin, L. Bardoczi, L. Baylor, I. Bykov, T. N. Carlstrom, D. Kaplan, C. J. Lasnier, A. Lvovskiy, A. Moser, R. A. Moyer, C. Paz-Soldan, D. L. Rudakov, C. Samuell, M. ShaferM. Van Zeeland, A. Welander, R. Wilcox

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Abstract

The assimilation of argon injected into post-disruption runaway electron (RE) plateaus is studied and compared to the vertical loss rate for vertically unstable RE plateaus. A 1D diffusion model is developed to include neutral diffusion and ionization and is used to help in data interpretation. It is found that the radial mixing time scale of argon ions (∼0.05 s) is comparable to the vertical loss timescale. Neutral argon becomes the dominant Ar species in the RE plateau for large Ar numbers (> 3 × 10²¹); at the same time the neutral Ar diffusivity decreases due to plasma cooling, causing a saturation in the assimilation of injected Ar on the vertical loss time scale. Injection of Ar into vertically unstable RE plateaus in DIII-D does increase the vertical loss rate, as predicted by previous modeling of ITER. However, there is a decreasing trend in RE current at the wall strike as the Ar quantity is turned up or as the Ar is injected earlier, indicating a decrease in RE energy deposited to the wall.

Original language	English
Article number	106014
Journal	Nuclear Fusion
Volume	59
Issue number	10
DOIs	https://doi.org/10.1088/1741-4326/ab32b2
State	Published - Aug 21 2019

Keywords

disruption
runaway electrons
tokamak

UN SDGs

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

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10.1088/1741-4326/ab32b2

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Hollmann, E. M., Eidietis, N. W., Herfindal, J. L., Parks, P. B., Pigarov, A. Y., Shiraki, D., Austin, M. E., Bardoczi, L., Baylor, L., Bykov, I., Carlstrom, T. N., Kaplan, D., Lasnier, C. J., Lvovskiy, A., Moser, A., Moyer, R. A., Paz-Soldan, C., Rudakov, D. L., Samuell, C., ... Wilcox, R. (2019). Study of argon assimilation into the post-disruption runaway electron plateau in DIII-D and comparison with a 1D diffusion model. Nuclear Fusion, 59(10), Article 106014. https://doi.org/10.1088/1741-4326/ab32b2

@article{25c3cf4eed6e46199067028fa72eb619,

title = "Study of argon assimilation into the post-disruption runaway electron plateau in DIII-D and comparison with a 1D diffusion model",

abstract = "The assimilation of argon injected into post-disruption runaway electron (RE) plateaus is studied and compared to the vertical loss rate for vertically unstable RE plateaus. A 1D diffusion model is developed to include neutral diffusion and ionization and is used to help in data interpretation. It is found that the radial mixing time scale of argon ions (∼0.05 s) is comparable to the vertical loss timescale. Neutral argon becomes the dominant Ar species in the RE plateau for large Ar numbers (> 3 × 1021); at the same time the neutral Ar diffusivity decreases due to plasma cooling, causing a saturation in the assimilation of injected Ar on the vertical loss time scale. Injection of Ar into vertically unstable RE plateaus in DIII-D does increase the vertical loss rate, as predicted by previous modeling of ITER. However, there is a decreasing trend in RE current at the wall strike as the Ar quantity is turned up or as the Ar is injected earlier, indicating a decrease in RE energy deposited to the wall.",

keywords = "disruption, runaway electrons, tokamak",

author = "Hollmann, {E. M.} and Eidietis, {N. W.} and Herfindal, {J. L.} and Parks, {P. B.} and Pigarov, {A. Y.} and D. Shiraki and Austin, {M. E.} and L. Bardoczi and L. Baylor and I. Bykov and Carlstrom, {T. N.} and D. Kaplan and Lasnier, {C. J.} and A. Lvovskiy and A. Moser and Moyer, {R. A.} and C. Paz-Soldan and Rudakov, {D. L.} and C. Samuell and M. Shafer and {Van Zeeland}, M. and A. Welander and R. Wilcox",

year = "2019",

month = aug,

day = "21",

doi = "10.1088/1741-4326/ab32b2",

language = "English",

volume = "59",

journal = "Nuclear Fusion",

issn = "0029-5515",

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Hollmann, EM, Eidietis, NW, Herfindal, JL, Parks, PB, Pigarov, AY, Shiraki, D, Austin, ME, Bardoczi, L, Baylor, L, Bykov, I, Carlstrom, TN, Kaplan, D, Lasnier, CJ, Lvovskiy, A, Moser, A, Moyer, RA, Paz-Soldan, C, Rudakov, DL, Samuell, C, Shafer, M, Van Zeeland, M, Welander, A & Wilcox, R 2019, 'Study of argon assimilation into the post-disruption runaway electron plateau in DIII-D and comparison with a 1D diffusion model', Nuclear Fusion, vol. 59, no. 10, 106014. https://doi.org/10.1088/1741-4326/ab32b2

TY - JOUR

T1 - Study of argon assimilation into the post-disruption runaway electron plateau in DIII-D and comparison with a 1D diffusion model

AU - Hollmann, E. M.

AU - Eidietis, N. W.

AU - Herfindal, J. L.

AU - Parks, P. B.

AU - Pigarov, A. Y.

AU - Shiraki, D.

AU - Austin, M. E.

AU - Bardoczi, L.

AU - Baylor, L.

AU - Bykov, I.

AU - Carlstrom, T. N.

AU - Kaplan, D.

AU - Lasnier, C. J.

AU - Lvovskiy, A.

AU - Moser, A.

AU - Moyer, R. A.

AU - Paz-Soldan, C.

AU - Rudakov, D. L.

AU - Samuell, C.

AU - Shafer, M.

AU - Van Zeeland, M.

AU - Welander, A.

AU - Wilcox, R.

PY - 2019/8/21

Y1 - 2019/8/21

N2 - The assimilation of argon injected into post-disruption runaway electron (RE) plateaus is studied and compared to the vertical loss rate for vertically unstable RE plateaus. A 1D diffusion model is developed to include neutral diffusion and ionization and is used to help in data interpretation. It is found that the radial mixing time scale of argon ions (∼0.05 s) is comparable to the vertical loss timescale. Neutral argon becomes the dominant Ar species in the RE plateau for large Ar numbers (> 3 × 1021); at the same time the neutral Ar diffusivity decreases due to plasma cooling, causing a saturation in the assimilation of injected Ar on the vertical loss time scale. Injection of Ar into vertically unstable RE plateaus in DIII-D does increase the vertical loss rate, as predicted by previous modeling of ITER. However, there is a decreasing trend in RE current at the wall strike as the Ar quantity is turned up or as the Ar is injected earlier, indicating a decrease in RE energy deposited to the wall.

AB - The assimilation of argon injected into post-disruption runaway electron (RE) plateaus is studied and compared to the vertical loss rate for vertically unstable RE plateaus. A 1D diffusion model is developed to include neutral diffusion and ionization and is used to help in data interpretation. It is found that the radial mixing time scale of argon ions (∼0.05 s) is comparable to the vertical loss timescale. Neutral argon becomes the dominant Ar species in the RE plateau for large Ar numbers (> 3 × 1021); at the same time the neutral Ar diffusivity decreases due to plasma cooling, causing a saturation in the assimilation of injected Ar on the vertical loss time scale. Injection of Ar into vertically unstable RE plateaus in DIII-D does increase the vertical loss rate, as predicted by previous modeling of ITER. However, there is a decreasing trend in RE current at the wall strike as the Ar quantity is turned up or as the Ar is injected earlier, indicating a decrease in RE energy deposited to the wall.

KW - disruption

KW - runaway electrons

KW - tokamak

UR - http://www.scopus.com/inward/record.url?scp=85072715288&partnerID=8YFLogxK

U2 - 10.1088/1741-4326/ab32b2

DO - 10.1088/1741-4326/ab32b2

M3 - Article

AN - SCOPUS:85072715288

SN - 0029-5515

VL - 59

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 10

M1 - 106014

ER -

Study of argon assimilation into the post-disruption runaway electron plateau in DIII-D and comparison with a 1D diffusion model

Abstract

Keywords

UN SDGs

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