Alpha particle diagnostics using impurity pellet injection

Conference · Fri May 01 04:00:00 EDT 1992

OSTI ID:5188015

Fisher, R K; McChesney, J M; Howald, A W; Parks, P B ^[1]; Snipes, J A; Terry, J L; Marmar, E S ^[2]; Zweben, S J; Medley, S S ^[3]

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1. General Atomics, San Diego, CA (United States)
2. Massachusetts Inst. of Tech., Cambridge, MA (United States)
3. Princeton Univ., NJ (United States). Plasma Physics Lab.

We have proposed using impurity injection to measure the energy distribution of the fast confined alpha particles in a reacting plasma. The ablation cloud surrounding the injected pellet is thick enough that an equilibrium fraction F{sub o}{sup {infinity}}(E) of the incident alphas should be neutralized as they pass through the cloud. By observing neutrals created in the large spatial region of the cloud which is expected to be dominated by the helium-like ionization state, e.g., Li{sup +} ions, we can determine the incident alpha distribution dn{sub He}2+/dE from the measured energy distribution of neutral helium atoms. Initial experiments were performed on TEXT in which we compared pellet penetration with our impurity pellet ablation model, and measured the spatial distribution of various ionization states in carbon pellet clouds. Experiments have recently begun on TFTR with the goal of measuring the alpha particle energy distribution during D-T operation in 1993--94. A series of preliminary experiments are planned to test the diagnostic concept. The first experiments will observe neutrals from beam-injected deuterium ions and the high energy {sup 3}He tail produced during ICH minority heating on TFTR interacting with the cloud. We will also monitor by line radiation the charge state distributions in lithium, boron, and carbon clouds.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-89ER53277; FG02-90ER54084; AC02-76CH03073
• OSTI ID: 5188015
• Report Number(s): GA-A-20870; CONF-920362--31; ON: DE92013796
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700330* -- Plasma Kinetics
Transport
& Impurities-- (1992-)
ALPHA PARTICLES
CHARGE EXCHANGE
CHARGED PARTICLES
CLOSED PLASMA DEVICES
HEATING
HIGH-FREQUENCY HEATING
ICR HEATING
PELLET INJECTION
PLASMA DIAGNOSTICS
PLASMA HEATING
TFTR TOKAMAK
THERMONUCLEAR DEVICES
TOKAMAK DEVICES