Effect of ELMs on rotation and momentum confinement in H-mode discharges in JET

JET-EFDA collaborators

Research output: Contribution to journalArticleScientificpeer-review

15 Citations (Scopus)

Abstract

The loss of plasma toroidal angular momentum and thermal energy by edge localized modes (ELMs) has been studied in JET. The analysis shows a consistently larger drop in momentum in comparison with the energy loss associated with the ELMs. This difference originates from the large reduction in angular frequency at the plasma edge, observed to penetrate into the plasma up to r/a ~ 0.65 during large type-I ELMs. As a result, the time averaged angular frequency is lowered near the top of the pedestal with increasing ELM frequency, resulting in a significant drop in thermal Mach number at the edge. An increase in profile peaking of ion temperature and angular frequency is observed. At the same time the plasma confinement is reduced while the ratio of confinement times (Rτ = τE) increases noticeably with ELM frequency. This change could be explained by the relatively larger ELM induced losses for momentum in combination with the observed longer build-up time for the momentum density at the plasma edge.
Original languageEnglish
Article number045014
Number of pages12
JournalPlasma Physics and Controlled Fusion
Volume52
Issue number4
DOIs
Publication statusPublished - 2010
MoE publication typeA1 Journal article-refereed

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Momentum
momentum
Plasmas
Plasma confinement
Angular momentum
Thermal energy
Mach number
Energy dissipation
Ions
plasma control
toroidal plasmas
ion temperature
thermal energy
angular momentum
energy dissipation
kinetic energy
Temperature
profiles

Cite this

@article{34fc68993c974f52a9383905f50d81fe,
title = "Effect of ELMs on rotation and momentum confinement in H-mode discharges in JET",
abstract = "The loss of plasma toroidal angular momentum and thermal energy by edge localized modes (ELMs) has been studied in JET. The analysis shows a consistently larger drop in momentum in comparison with the energy loss associated with the ELMs. This difference originates from the large reduction in angular frequency at the plasma edge, observed to penetrate into the plasma up to r/a ~ 0.65 during large type-I ELMs. As a result, the time averaged angular frequency is lowered near the top of the pedestal with increasing ELM frequency, resulting in a significant drop in thermal Mach number at the edge. An increase in profile peaking of ion temperature and angular frequency is observed. At the same time the plasma confinement is reduced while the ratio of confinement times (Rτ = τE/τ) increases noticeably with ELM frequency. This change could be explained by the relatively larger ELM induced losses for momentum in combination with the observed longer build-up time for the momentum density at the plasma edge.",
author = "Versloot, {T. W.} and {de Vries}, {P. C.} and C. Giroud and M.-D. Hua and Beurskens, {M. N. A.} and M. Brix and T. Eich and {De La Luna}, E. and Tuomas Tala and V. Naulin and Zastrow, {K. D.} and {JET-EFDA collaborators}",
year = "2010",
doi = "10.1088/0741-3335/52/4/045014",
language = "English",
volume = "52",
journal = "Plasma Physics and Controlled Fusion",
issn = "0741-3335",
publisher = "Institute of Physics IOP",
number = "4",

}

Effect of ELMs on rotation and momentum confinement in H-mode discharges in JET. / JET-EFDA collaborators.

In: Plasma Physics and Controlled Fusion, Vol. 52, No. 4, 045014, 2010.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Effect of ELMs on rotation and momentum confinement in H-mode discharges in JET

AU - Versloot, T. W.

AU - de Vries, P. C.

AU - Giroud, C.

AU - Hua, M.-D.

AU - Beurskens, M. N. A.

AU - Brix, M.

AU - Eich, T.

AU - De La Luna, E.

AU - Tala, Tuomas

AU - Naulin, V.

AU - Zastrow, K. D.

AU - JET-EFDA collaborators

PY - 2010

Y1 - 2010

N2 - The loss of plasma toroidal angular momentum and thermal energy by edge localized modes (ELMs) has been studied in JET. The analysis shows a consistently larger drop in momentum in comparison with the energy loss associated with the ELMs. This difference originates from the large reduction in angular frequency at the plasma edge, observed to penetrate into the plasma up to r/a ~ 0.65 during large type-I ELMs. As a result, the time averaged angular frequency is lowered near the top of the pedestal with increasing ELM frequency, resulting in a significant drop in thermal Mach number at the edge. An increase in profile peaking of ion temperature and angular frequency is observed. At the same time the plasma confinement is reduced while the ratio of confinement times (Rτ = τE/τ) increases noticeably with ELM frequency. This change could be explained by the relatively larger ELM induced losses for momentum in combination with the observed longer build-up time for the momentum density at the plasma edge.

AB - The loss of plasma toroidal angular momentum and thermal energy by edge localized modes (ELMs) has been studied in JET. The analysis shows a consistently larger drop in momentum in comparison with the energy loss associated with the ELMs. This difference originates from the large reduction in angular frequency at the plasma edge, observed to penetrate into the plasma up to r/a ~ 0.65 during large type-I ELMs. As a result, the time averaged angular frequency is lowered near the top of the pedestal with increasing ELM frequency, resulting in a significant drop in thermal Mach number at the edge. An increase in profile peaking of ion temperature and angular frequency is observed. At the same time the plasma confinement is reduced while the ratio of confinement times (Rτ = τE/τ) increases noticeably with ELM frequency. This change could be explained by the relatively larger ELM induced losses for momentum in combination with the observed longer build-up time for the momentum density at the plasma edge.

U2 - 10.1088/0741-3335/52/4/045014

DO - 10.1088/0741-3335/52/4/045014

M3 - Article

VL - 52

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

SN - 0741-3335

IS - 4

M1 - 045014

ER -