Development of Li sup minus and H sup minus ion sources

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6048867

Walther, S R

Sources of Li{sup {minus}} and H{sup {minus}} ions are needed for diagnostic neutral beams 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- 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.

• Research Organization: California Univ., Berkeley, CA (USA)
• OSTI ID: 6048867
• 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
ANIONS
BARIUM
CESIUM
CHARGED PARTICLES
CLOSED PLASMA DEVICES
COMPARATIVE EVALUATIONS
CURRENT DENSITY
CURRENT-DRIVE HEATING
DATA
ELECTRIC HEATING
ELEMENTS
EXPERIMENTAL DATA
FUNCTIONS
HEATING
HYDROGEN IONS
HYDROGEN IONS 1 MINUS
INFORMATION
ION SOURCES
IONS
ITER TOKAMAK
JOULE HEATING
LITHIUM IONS
MATHEMATICAL MODELS
METALS
NEUTRAL BEAM SOURCES
NUMERICAL DATA
PERFORMANCE
PLASMA
PLASMA DIAGNOSTICS
PLASMA HEATING
RESISTANCE HEATING
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
USES
WORK FUNCTIONS