Problems of gas control and fueling in the Tara tandem mirror
Control of the edge neutral pressure is critical for successful thermal barrier operation of tandem mirrors. High neutral pressures lead to substantial charge exchange losses of plasma ions as well as creating a population of cold ions and electrons which may be electrostatically trapped in the negative and positive confining potentials in the end cells. The primary sources of neutral gas in Tara are central cell and transition gas injection, and neutral beam injection in the plugs. In the central cell, the region of ionization is separated from the mirror-trapped hot ion region. Gettering in the region of hot ions, controls reflux and reduces the central cell gas contribution to the plug. During end plugging, the plasma stream from the central cell which is used to fuel the minimum B anchor cells is cut off, so that gas fueling must be supplied in the transition region. The beamlines and dumps use LN/Ti pumps, baffling and bakeable dumps and scrapers to limit gas penetration to the plug plasma. Gettering of the plug wall and geometric considerations are used to control reflux from charge exchange. Monte-Carlo simulations are used to analyze the plug and central cell reflux. A new central cell configuration employing a midplane magnetic divertor is now being evaluated. The halo plasma produced in the diverted magnetic flux will be used to improve shielding of the core plasma from charge exchange.
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge (USA). Plasma Fusion Center
- DOE Contract Number:
- AC02-78ET51013
- OSTI ID:
- 7067805
- Report Number(s):
- DOE/ET/51013-203; PFC/CP-86-18; CONF-861019-24; ON: DE87005999
- Resource Relation:
- Conference: 10. international vacuum congress and 6. international conference on solid surfaces and the 33. national symposium of the American Vacuum Society, Baltimore, MD, USA, 27 Oct 1986; Other Information: Microfiche only, copy does not permit paper copy reproduction
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
TARA DEVICES
PLASMA SCRAPE-OFF LAYER
THERMAL BARRIERS
CHARGE EXCHANGE
ENERGY LOSSES
GAS INJECTION
GETTERING
MONTE CARLO METHOD
NEUTRAL ATOM BEAM INJECTION
PLUGGING
REACTOR FUELING
TITANIUM
BEAM INJECTION
BOUNDARY LAYERS
ELEMENTS
FLUID INJECTION
LAYERS
LOSSES
MAGNETIC MIRRORS
METALS
OPEN PLASMA DEVICES
TANDEM MIRRORS
THERMONUCLEAR DEVICES
TRANSITION ELEMENTS
700103* - Fusion Energy- Plasma Research- Kinetics