Mitigation of divertor edge localised mode power loading by impurity seeding

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389021%3A_____%2F23%3A00584141" target="_blank" >RIV/61389021:_____/23:00584141 - isvavai.cz</a>

Výsledek na webu

<a href="https://iopscience.iop.org/article/10.1088/1741-4326/acf4aa" target="_blank" >https://iopscience.iop.org/article/10.1088/1741-4326/acf4aa</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/1741-4326/acf4aa" target="_blank" >10.1088/1741-4326/acf4aa</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Mitigation of divertor edge localised mode power loading by impurity seeding

Popis výsledku v původním jazyce

One of the major challenges for the design of future thermonuclear reactors is the problem of power exhaust—the removal of heat fluxes deposited by plasma particles onto the plasma-facing components (PFCs) of the reactor wall. In order for the reactor to work efficiently, the power loading of the PFCs has to stay within their material limits. A substantial part of these heat fluxes can be deposited transiently during the impact of edge localised modes (ELMs), which typically accompany the high confinement mode, a regime foreseen for tokamak ITER and next-step devices. One of the possible ways to mitigate the deposition of localised heat fluxes during ELMs is injection of impurities, which could similarly to inter-ELM detachment dissipate part of the energy carried by plasma particles, the so-called ELM buffering effect. In this contribution, we report on experimental observations in impurity seeded discharges in ASDEX Upgrade, where injection of argon is capable of reducing the ELM energy by up to 80 % (60 % without degradation of confinement). A simple model of ELM cooling is in some cases capable of providing quantitative prediction of this effect. The ELM peak energy fluence ϵ | | , p e a k was reduced by a factor 8 without a degradation of the pedestal pressure. Should such mitigation be achieved in ITER, the resulting power loading would satisfy the material limits of divertor tungsten monoblocks (Eich et al 2017 Nucl. Mater. Energy 12 84-90) and as such avoid the risk of their melting. The most favourable results in terms of confinement and divertor heat flux mitigation were achieved by use of a mixture of argon and nitrogen, where the later impurity helped to improve the confinement. The ELM frequency was identified as a scaling factor for ϵ | | , p e a k in discharges with impurity seeding, suggesting that high frequency ELMs are favourable for future devices.

Název v anglickém jazyce

Mitigation of divertor edge localised mode power loading by impurity seeding

Popis výsledku anglicky

One of the major challenges for the design of future thermonuclear reactors is the problem of power exhaust—the removal of heat fluxes deposited by plasma particles onto the plasma-facing components (PFCs) of the reactor wall. In order for the reactor to work efficiently, the power loading of the PFCs has to stay within their material limits. A substantial part of these heat fluxes can be deposited transiently during the impact of edge localised modes (ELMs), which typically accompany the high confinement mode, a regime foreseen for tokamak ITER and next-step devices. One of the possible ways to mitigate the deposition of localised heat fluxes during ELMs is injection of impurities, which could similarly to inter-ELM detachment dissipate part of the energy carried by plasma particles, the so-called ELM buffering effect. In this contribution, we report on experimental observations in impurity seeded discharges in ASDEX Upgrade, where injection of argon is capable of reducing the ELM energy by up to 80 % (60 % without degradation of confinement). A simple model of ELM cooling is in some cases capable of providing quantitative prediction of this effect. The ELM peak energy fluence ϵ | | , p e a k was reduced by a factor 8 without a degradation of the pedestal pressure. Should such mitigation be achieved in ITER, the resulting power loading would satisfy the material limits of divertor tungsten monoblocks (Eich et al 2017 Nucl. Mater. Energy 12 84-90) and as such avoid the risk of their melting. The most favourable results in terms of confinement and divertor heat flux mitigation were achieved by use of a mixture of argon and nitrogen, where the later impurity helped to improve the confinement. The ELM frequency was identified as a scaling factor for ϵ | | , p e a k in discharges with impurity seeding, suggesting that high frequency ELMs are favourable for future devices.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10305 - Fluids and plasma physics (including surface physics)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2023

Kód důvěrnosti údajů

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

Název periodika

Nuclear Fusion

ISSN

0029-5515

e-ISSN

1741-4326

Svazek periodika

63

Číslo periodika v rámci svazku

12

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

12

Strana od-do

126018

Kód UT WoS článku

001073366400001

EID výsledku v databázi Scopus

2-s2.0-85174270451