Application of secondary ion emission to impurity control in tokamaks
Abstract
The extent to which high Z impurities enter the plasma of a magnetic confinement fusion device depends on the kinetic energy, angle of emission, and very importantly, the charge state of the ejected material. Both the fundamental process of secondary ion emission and possible techniques for producing surfaces which give rise to high ion fraction during sputtering are studied with a view to assessing the potential of this approach to impurity control in Tokamaks. By carefully choosing materials exposed to fusion plasmas and by properly modifying the surface it may be possible to insure that nearly all the impurities are ejected as ions. As long as certain gas blanket configurations are avoided and especially if a divertor is used, it should then be possible to remove the impurities before they reach the plasma. The relative merits of a variety of materials are considered with regard to this application.
- Publication:
-
Presented at 1st Topical Meeting on Fusion Reactor Materials
- Pub Date:
- 1979
- Bibcode:
- 1979frm..meetQ....K
- Keywords:
-
- Impurities;
- Ion Emission;
- Ionized Gases;
- Plasma Composition;
- Secondary Emission;
- Tokamak Devices;
- Alkali Metals;
- Blankets (Fusion Reactors);
- Energy Distribution;
- Kinetic Energy;
- Lithium Compounds;
- Sputtering;
- Plasma Physics