Enhanced energy confinement after series of pellets in Wendelstein 7-X

J. Baldzuhn; H. Damm; C. D. Beidler; K. Mccarthy; N. Panadero; C. Biedermann; S. A. Bozhenkov; A. Dinklage; K. J. Brunner; G. Fuchert; Y. Kazakov; M. Beurskens; M. Dibon; J. Geiger; O. Grulke; U. Höfel; T. Klinger; F. Köchl; J. Knauer; G. Kocsis; P. Kornejew; P. T. Lang; A. Langenberg; H. Laqua; N. A. Pablant; E. Pasch; T. S. Pedersen; B. Ploeckl; K. Rahbarnia; G. Schlisio; E. R. Scott; T. Stange; A. Von Stechow; T. Szepesi; Y. Turkin; F. Wagner; V. Winters; G. Wurden; D. Zhang

doi:10.1088/1361-6587/ab8112

Enhanced energy confinement after series of pellets in Wendelstein 7-X

J. Baldzuhn, H. Damm, C. D. Beidler, K. Mccarthy, N. Panadero, C. Biedermann, S. A. Bozhenkov, A. Dinklage, K. J. Brunner, G. Fuchert, Y. Kazakov, M. Beurskens, M. Dibon, J. Geiger, O. Grulke, U. Höfel, T. Klinger, F. Köchl, J. Knauer, G. KocsisP. Kornejew, P. T. Lang, A. Langenberg, H. Laqua, N. A. Pablant, E. Pasch, T. S. Pedersen, B. Ploeckl, K. Rahbarnia, G. Schlisio, E. R. Scott, T. Stange, A. Von Stechow, T. Szepesi, Y. Turkin, F. Wagner, V. Winters, G. Wurden, D. Zhang

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Abstract

A series of ice pellets was injected into the advanced stellarator Wendelstein 7-X (W7-X). Although the pellets were small and slow, deep and efficient particle fueling could be observed experimentally. The most striking feature appearing after the injection of the pellets, however, was a transient increase in the energy confinement time. This transient phase resembled in several aspects modes of enhanced confinement after gas-puff or pellet injection, as observed in other fusion experiments. All experimental attempts, to prolong this phase, failed. In this paper, discharges are described that show the enhanced energy confinement, and some conditions are summarized which seem to be essential in order to generate it. The focus here is on deep particle fueling by pellets, and shaping of the density profiles during and after the series of pellets. During this time, neutral gas particle re-fueling at the plasma edge is reduced, while density profile peaking and low impurity radiation losses are present.

Original language	English (US)
Article number	055012
Journal	Plasma Physics and Controlled Fusion
Volume	62
Issue number	5
DOIs	https://doi.org/10.1088/1361-6587/ab8112
State	Published - May 2020

All Science Journal Classification (ASJC) codes

Nuclear Energy and Engineering
Condensed Matter Physics

Keywords

energy transport
ice pellet injection
particle transport

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10.1088/1361-6587/ab8112

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Baldzuhn, J., Damm, H., Beidler, C. D., Mccarthy, K., Panadero, N., Biedermann, C., Bozhenkov, S. A., Dinklage, A., Brunner, K. J., Fuchert, G., Kazakov, Y., Beurskens, M., Dibon, M., Geiger, J., Grulke, O., Höfel, U., Klinger, T., Köchl, F., Knauer, J., ... Zhang, D. (2020). Enhanced energy confinement after series of pellets in Wendelstein 7-X. Plasma Physics and Controlled Fusion, 62(5), Article 055012. https://doi.org/10.1088/1361-6587/ab8112

@article{ad2e8a90ffe341408ccc403f876952b4,

title = "Enhanced energy confinement after series of pellets in Wendelstein 7-X",

abstract = "A series of ice pellets was injected into the advanced stellarator Wendelstein 7-X (W7-X). Although the pellets were small and slow, deep and efficient particle fueling could be observed experimentally. The most striking feature appearing after the injection of the pellets, however, was a transient increase in the energy confinement time. This transient phase resembled in several aspects modes of enhanced confinement after gas-puff or pellet injection, as observed in other fusion experiments. All experimental attempts, to prolong this phase, failed. In this paper, discharges are described that show the enhanced energy confinement, and some conditions are summarized which seem to be essential in order to generate it. The focus here is on deep particle fueling by pellets, and shaping of the density profiles during and after the series of pellets. During this time, neutral gas particle re-fueling at the plasma edge is reduced, while density profile peaking and low impurity radiation losses are present.",

keywords = "energy transport, ice pellet injection, particle transport",

author = "J. Baldzuhn and H. Damm and Beidler, \{C. D.\} and K. Mccarthy and N. Panadero and C. Biedermann and Bozhenkov, \{S. A.\} and A. Dinklage and Brunner, \{K. J.\} and G. Fuchert and Y. Kazakov and M. Beurskens and M. Dibon and J. Geiger and O. Grulke and U. H{\"o}fel and T. Klinger and F. K{\"o}chl and J. Knauer and G. Kocsis and P. Kornejew and Lang, \{P. T.\} and A. Langenberg and H. Laqua and Pablant, \{N. A.\} and E. Pasch and Pedersen, \{T. S.\} and B. Ploeckl and K. Rahbarnia and G. Schlisio and Scott, \{E. R.\} and T. Stange and \{Von Stechow\}, A. and T. Szepesi and Y. Turkin and F. Wagner and V. Winters and G. Wurden and D. Zhang",

note = "Publisher Copyright: {\textcopyright} Max-Planck-Institut f{\"u}r Plasmaphysik.",

year = "2020",

month = may,

doi = "10.1088/1361-6587/ab8112",

language = "English (US)",

volume = "62",

journal = "Plasma Physics and Controlled Fusion",

issn = "0741-3335",

publisher = "IOP Publishing Ltd.",

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Baldzuhn, J, Damm, H, Beidler, CD, Mccarthy, K, Panadero, N, Biedermann, C, Bozhenkov, SA, Dinklage, A, Brunner, KJ, Fuchert, G, Kazakov, Y, Beurskens, M, Dibon, M, Geiger, J, Grulke, O, Höfel, U, Klinger, T, Köchl, F, Knauer, J, Kocsis, G, Kornejew, P, Lang, PT, Langenberg, A, Laqua, H, Pablant, NA, Pasch, E, Pedersen, TS, Ploeckl, B, Rahbarnia, K, Schlisio, G, Scott, ER, Stange, T, Von Stechow, A, Szepesi, T, Turkin, Y, Wagner, F, Winters, V, Wurden, G & Zhang, D 2020, 'Enhanced energy confinement after series of pellets in Wendelstein 7-X', Plasma Physics and Controlled Fusion, vol. 62, no. 5, 055012. https://doi.org/10.1088/1361-6587/ab8112

TY - JOUR

T1 - Enhanced energy confinement after series of pellets in Wendelstein 7-X

AU - Baldzuhn, J.

AU - Damm, H.

AU - Beidler, C. D.

AU - Mccarthy, K.

AU - Panadero, N.

AU - Biedermann, C.

AU - Bozhenkov, S. A.

AU - Dinklage, A.

AU - Brunner, K. J.

AU - Fuchert, G.

AU - Kazakov, Y.

AU - Beurskens, M.

AU - Dibon, M.

AU - Geiger, J.

AU - Grulke, O.

AU - Höfel, U.

AU - Klinger, T.

AU - Köchl, F.

AU - Knauer, J.

AU - Kocsis, G.

AU - Kornejew, P.

AU - Lang, P. T.

AU - Langenberg, A.

AU - Laqua, H.

AU - Pablant, N. A.

AU - Pasch, E.

AU - Pedersen, T. S.

AU - Ploeckl, B.

AU - Rahbarnia, K.

AU - Schlisio, G.

AU - Scott, E. R.

AU - Stange, T.

AU - Von Stechow, A.

AU - Szepesi, T.

AU - Turkin, Y.

AU - Wagner, F.

AU - Winters, V.

AU - Wurden, G.

AU - Zhang, D.

PY - 2020/5

Y1 - 2020/5

N2 - A series of ice pellets was injected into the advanced stellarator Wendelstein 7-X (W7-X). Although the pellets were small and slow, deep and efficient particle fueling could be observed experimentally. The most striking feature appearing after the injection of the pellets, however, was a transient increase in the energy confinement time. This transient phase resembled in several aspects modes of enhanced confinement after gas-puff or pellet injection, as observed in other fusion experiments. All experimental attempts, to prolong this phase, failed. In this paper, discharges are described that show the enhanced energy confinement, and some conditions are summarized which seem to be essential in order to generate it. The focus here is on deep particle fueling by pellets, and shaping of the density profiles during and after the series of pellets. During this time, neutral gas particle re-fueling at the plasma edge is reduced, while density profile peaking and low impurity radiation losses are present.

AB - A series of ice pellets was injected into the advanced stellarator Wendelstein 7-X (W7-X). Although the pellets were small and slow, deep and efficient particle fueling could be observed experimentally. The most striking feature appearing after the injection of the pellets, however, was a transient increase in the energy confinement time. This transient phase resembled in several aspects modes of enhanced confinement after gas-puff or pellet injection, as observed in other fusion experiments. All experimental attempts, to prolong this phase, failed. In this paper, discharges are described that show the enhanced energy confinement, and some conditions are summarized which seem to be essential in order to generate it. The focus here is on deep particle fueling by pellets, and shaping of the density profiles during and after the series of pellets. During this time, neutral gas particle re-fueling at the plasma edge is reduced, while density profile peaking and low impurity radiation losses are present.

KW - energy transport

KW - ice pellet injection

KW - particle transport

UR - https://www.scopus.com/pages/publications/85084582663

UR - https://www.scopus.com/inward/citedby.url?scp=85084582663&partnerID=8YFLogxK

U2 - 10.1088/1361-6587/ab8112

DO - 10.1088/1361-6587/ab8112

M3 - Article

AN - SCOPUS:85084582663

SN - 0741-3335

VL - 62

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

IS - 5

M1 - 055012

ER -

Enhanced energy confinement after series of pellets in Wendelstein 7-X

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