Back to Search
Start Over
Gas jet disruption mitigation studies on Alcator C-Mod
- Source :
- Nuclear Fusion. 46:1001-1008
- Publication Year :
- 2006
- Publisher :
- IOP Publishing, 2006.
-
Abstract
- Damaging effects of disruptions are a major concern for Alcator C-Mod, ITER and future tokamak reactors. High-pressure noble gas jet injection is a mitigation technique which potentially satisfies the operational requirements of fast response time and reliability, while still being benign to subsequent discharges. Disruption mitigation experiments using an optimized gas jet injection system are being carried out on Alcator C-Mod to study the physics of gas jet penetration into high pressure plasmas, as well as the ability of the gas jet impurities to convert plasma energy into radiation on timescales consistent with C-Mod's fast quench times, and to reduce halo currents given C-Mod's high-current density. The dependence of impurity penetration and effectiveness on noble gas species (He, Ne, Ar, Kr) is also being studied. It is found that the high-pressure neutral gas jet does not penetrate deeply into the C-Mod plasma, and yet prompt core thermal quenches are observed on all gas jet shots. 3D MHD modelling of the disruption physics with NIMROD shows that edge cooling of the plasma triggers fast growing tearing modes which rapidly produce a stochastic region in the core of the plasma and loss of thermal energy. This may explain the apparent effectiveness of the gas jet in C-Mod despite its limited penetration. The higher-Z gases (Ne, Ar, Kr) also proved effective at reducing halo currents and decreasing thermal deposition to the divertor surfaces. In addition, noble gas jet injection proved to be benign for plasma operation with C-Mod's metal (Mo) wall, actually improving the reliability of the startup in the following discharge.
- Subjects :
- Nuclear and High Energy Physics
Tokamak
Materials science
business.industry
Divertor
Nuclear engineering
Magnetic confinement fusion
Noble gas
Atmospheric-pressure plasma
Plasma
Condensed Matter Physics
law.invention
Alcator C-Mod
Physics::Plasma Physics
law
Atomic physics
business
Thermal energy
Subjects
Details
- ISSN :
- 17414326 and 00295515
- Volume :
- 46
- Database :
- OpenAIRE
- Journal :
- Nuclear Fusion
- Accession number :
- edsair.doi...........a1ccc9c89a21e3a8d511164d6aff21ef