Disruptive locked mode instability after the l-h transition in the compass tokamak

Kód výsledku v IS VaVaI

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Výsledek na webu

<a href="https://ojs.cvut.cz/ojs/index.php/PPT/article/view/9980/7184" target="_blank" >https://ojs.cvut.cz/ojs/index.php/PPT/article/view/9980/7184</a>

DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Disruptive locked mode instability after the l-h transition in the compass tokamak

Popis výsledku v původním jazyce

Much effort has already been devoted to predicting the sensitivity of tokamaks to small asymmetric error fields (EFs), which are unavoidable in tokamak design and can drive dangerous locked-mode (LM) instabilities even at 0.1% amplitude. However, our experiments on COMPASS were the first to show that the threshold for triggering a LM during a transient phase of a tokamak discharge is much lower than in a steady state. This was observed for n=1 EF activated before the L-H transition at the ITER baseline plasma edge helicity. A threshold for EF penetration subsequent to the L-H transition is robustly obtained, showing no significant trend with density or applied external torque, and is explained by the reduced intrinsic rotation of the 2/1 mode during the transient. This finding cautions against using any parametric EF penetration scaling derived from steady-state experiments to define the error field correction strategy for the entire discharge.

Název v anglickém jazyce

Disruptive locked mode instability after the l-h transition in the compass tokamak

Popis výsledku anglicky

Much effort has already been devoted to predicting the sensitivity of tokamaks to small asymmetric error fields (EFs), which are unavoidable in tokamak design and can drive dangerous locked-mode (LM) instabilities even at 0.1% amplitude. However, our experiments on COMPASS were the first to show that the threshold for triggering a LM during a transient phase of a tokamak discharge is much lower than in a steady state. This was observed for n=1 EF activated before the L-H transition at the ITER baseline plasma edge helicity. A threshold for EF penetration subsequent to the L-H transition is robustly obtained, showing no significant trend with density or applied external torque, and is explained by the reduced intrinsic rotation of the 2/1 mode during the transient. This finding cautions against using any parametric EF penetration scaling derived from steady-state experiments to define the error field correction strategy for the entire discharge.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10305 - Fluids and plasma physics (including surface physics)

Projekt

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Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů