Department of Li/sup /minus// and H/sup /minus// ion sources

Technical Report · Thu Dec 01 04:00:00 EST 1988

DOI:https://doi.org/10.2172/6138995· OSTI ID:6138995

Walther, S R

Sources of Li/sup /minus// and H/sup /minus// ions are needed for diagnostic neutral beam and for current drive in fusion plasmas. Previous efforts to generate Li/sup /minus// beams have focused on electron capture in a gas or production on a low work function surface in a plasma. Volume production of Li/sup /minus// by dissociative attachment of optically pumped lithium molecules has also been studied. This thesis presents the first experimental results for volume production of a Li/sup /minus// ion beam from a plasma discharge. A theoretical model for volume production of Li/sup /minus// ions and separate model for Li/sub 2/ production in the lithium discharge are developed to explain the experimental results. The model is in good agreement with the experiment and shows favorable parameter scalings for further improvement of the Li/sup /minus// ion source. A /sup 6/Li/degree/ diagnostic neutral beam based on this ion source is proposed for measurement of magnetic pitch angle in the International Thermonuclear Experimental Reactor (ITER). Previous efforts in developing H/sup /minus// ion sources have concentrated on volume production in a plasma discharge. Experiments to improve the H/sup /minus// current density from a magnetically filtered multicusp ion source by seeding the discharge with cesium or barium have been conducted. A substantial (> factor of five) increase in H/sup /minus// output is achieved for both cesium and barium addition. Further experiments with barium have shown that the increase is due to H/sup /minus// production on the anode walls. The experiments with cesium are consistent with this formation mechanism. These results show that this new type of 'converterless' surface production H/sup /minus// source provides greatly improved performance when compared to a volume H/sup /minus// source. 92 refs., 47 figs.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6138995
• Report Number(s): LBL-26618; ON: DE89009975
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700102 -- Fusion Energy-- Plasma Research-- Diagnostics
700205* -- Fusion Power Plant Technology-- Fuel
Heating
& Injection Systems
ALKALI METALS
ALKALINE EARTH METALS
BARIUM
BEAM INJECTION
CAPTURE
CESIUM
CHARGED PARTICLES
CURRENT DENSITY
DESIGN
ELECTRON CAPTURE
ELEMENTS
HYDROGEN IONS
ION SOURCES
IONS
LITHIUM IONS
METALS
NEUTRAL ATOM BEAM INJECTION
PLASMA DIAGNOSTICS
THERMONUCLEAR REACTORS
USES