Impact of resonant magnetic perturbations on the L-H transition on MAST

R Scannell, A Kirk, M Carr, J Hawke, S S Henderson, T O'Gorman, A Patel, A. Shaw, A Thornton

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The impact of resonant magnetic perturbations (RMPs) on the power required to access H-mode is examined experimentally on MAST. Applying RMP in n = 2, 3, 4 and 6 configurations delays the L-H transition at low applied fields and prevents the transition at high fields. The experiment was primarily performed at RMP fields sufficient to cause moderate increases in ELM frequency, fmitigated/ fnatural ∼ 3. To obtain H-mode with RMPs at this field, an increase of injected beam power is required of at least 50% for n = 3 and n = 4 RMP and 100% for n = 6 RMP. In terms of power threshold, this corresponds to increases of at least 20% for n = 3 and n = 4 RMPs and 60% for n = 6 RMPs. This 'RMP affected' power threshold is found to increase with RMP magnitude above a certain minimum perturbed field, below which there is no impact on the power threshold. Extrapolations from these results indicate large increases in the L-H power threshold may be required for discharges requiring large mitigated ELM frequency.

LanguageEnglish
Article number075013
JournalPlasma Physics and Controlled Fusion
Volume57
Issue number7
DOIs
Publication statusPublished - 18 Jun 2015

Fingerprint

Extrapolation
perturbation
Experiments
thresholds
extrapolation
causes
configurations

Keywords

  • ELM frequency
  • L-H power threshold
  • L-H threshold
  • mitigated ELM frequency
  • resonant magentic perturbations
  • RMP

Cite this

Scannell, R., Kirk, A., Carr, M., Hawke, J., Henderson, S. S., O'Gorman, T., ... Thornton, A. (2015). Impact of resonant magnetic perturbations on the L-H transition on MAST. Plasma Physics and Controlled Fusion, 57(7), [075013]. https://doi.org/10.1088/0741-3335/57/7/075013
Scannell, R ; Kirk, A ; Carr, M ; Hawke, J ; Henderson, S S ; O'Gorman, T ; Patel, A ; Shaw, A. ; Thornton, A. / Impact of resonant magnetic perturbations on the L-H transition on MAST. In: Plasma Physics and Controlled Fusion. 2015 ; Vol. 57, No. 7.
@article{f627da54003740e9b972e97fad72cc02,
title = "Impact of resonant magnetic perturbations on the L-H transition on MAST",
abstract = "The impact of resonant magnetic perturbations (RMPs) on the power required to access H-mode is examined experimentally on MAST. Applying RMP in n = 2, 3, 4 and 6 configurations delays the L-H transition at low applied fields and prevents the transition at high fields. The experiment was primarily performed at RMP fields sufficient to cause moderate increases in ELM frequency, fmitigated/ fnatural ∼ 3. To obtain H-mode with RMPs at this field, an increase of injected beam power is required of at least 50{\%} for n = 3 and n = 4 RMP and 100{\%} for n = 6 RMP. In terms of power threshold, this corresponds to increases of at least 20{\%} for n = 3 and n = 4 RMPs and 60{\%} for n = 6 RMPs. This 'RMP affected' power threshold is found to increase with RMP magnitude above a certain minimum perturbed field, below which there is no impact on the power threshold. Extrapolations from these results indicate large increases in the L-H power threshold may be required for discharges requiring large mitigated ELM frequency.",
keywords = "ELM frequency, L-H power threshold, L-H threshold, mitigated ELM frequency, resonant magentic perturbations, RMP",
author = "R Scannell and A Kirk and M Carr and J Hawke and Henderson, {S S} and T O'Gorman and A Patel and A. Shaw and A Thornton",
year = "2015",
month = "6",
day = "18",
doi = "10.1088/0741-3335/57/7/075013",
language = "English",
volume = "57",
journal = "Plasma Physics and Controlled Fusion",
issn = "0741-3335",
number = "7",

}

Scannell, R, Kirk, A, Carr, M, Hawke, J, Henderson, SS, O'Gorman, T, Patel, A, Shaw, A & Thornton, A 2015, 'Impact of resonant magnetic perturbations on the L-H transition on MAST' Plasma Physics and Controlled Fusion, vol. 57, no. 7, 075013. https://doi.org/10.1088/0741-3335/57/7/075013

Impact of resonant magnetic perturbations on the L-H transition on MAST. / Scannell, R; Kirk, A; Carr, M; Hawke, J; Henderson, S S; O'Gorman, T; Patel, A; Shaw, A.; Thornton, A.

In: Plasma Physics and Controlled Fusion, Vol. 57, No. 7, 075013, 18.06.2015.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Impact of resonant magnetic perturbations on the L-H transition on MAST

AU - Scannell, R

AU - Kirk, A

AU - Carr, M

AU - Hawke, J

AU - Henderson, S S

AU - O'Gorman, T

AU - Patel, A

AU - Shaw, A.

AU - Thornton, A

PY - 2015/6/18

Y1 - 2015/6/18

N2 - The impact of resonant magnetic perturbations (RMPs) on the power required to access H-mode is examined experimentally on MAST. Applying RMP in n = 2, 3, 4 and 6 configurations delays the L-H transition at low applied fields and prevents the transition at high fields. The experiment was primarily performed at RMP fields sufficient to cause moderate increases in ELM frequency, fmitigated/ fnatural ∼ 3. To obtain H-mode with RMPs at this field, an increase of injected beam power is required of at least 50% for n = 3 and n = 4 RMP and 100% for n = 6 RMP. In terms of power threshold, this corresponds to increases of at least 20% for n = 3 and n = 4 RMPs and 60% for n = 6 RMPs. This 'RMP affected' power threshold is found to increase with RMP magnitude above a certain minimum perturbed field, below which there is no impact on the power threshold. Extrapolations from these results indicate large increases in the L-H power threshold may be required for discharges requiring large mitigated ELM frequency.

AB - The impact of resonant magnetic perturbations (RMPs) on the power required to access H-mode is examined experimentally on MAST. Applying RMP in n = 2, 3, 4 and 6 configurations delays the L-H transition at low applied fields and prevents the transition at high fields. The experiment was primarily performed at RMP fields sufficient to cause moderate increases in ELM frequency, fmitigated/ fnatural ∼ 3. To obtain H-mode with RMPs at this field, an increase of injected beam power is required of at least 50% for n = 3 and n = 4 RMP and 100% for n = 6 RMP. In terms of power threshold, this corresponds to increases of at least 20% for n = 3 and n = 4 RMPs and 60% for n = 6 RMPs. This 'RMP affected' power threshold is found to increase with RMP magnitude above a certain minimum perturbed field, below which there is no impact on the power threshold. Extrapolations from these results indicate large increases in the L-H power threshold may be required for discharges requiring large mitigated ELM frequency.

KW - ELM frequency

KW - L-H power threshold

KW - L-H threshold

KW - mitigated ELM frequency

KW - resonant magentic perturbations

KW - RMP

UR - http://www.scopus.com/inward/record.url?scp=84936750154&partnerID=8YFLogxK

UR - http://iopscience.iop.org/0741-3335/

U2 - 10.1088/0741-3335/57/7/075013

DO - 10.1088/0741-3335/57/7/075013

M3 - Article

VL - 57

JO - Plasma Physics and Controlled Fusion

T2 - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

SN - 0741-3335

IS - 7

M1 - 075013

ER -