A new alpha particle diagnostic using knock-on ion tails

Conference · Wed Jun 01 04:00:00 EDT 1994

OSTI ID:10170299

Fisher, R K; Parks, P B; McChesney, J M ^[1]; Rosenbluth, M N ^[2]

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1. General Atomics, San Diego, CA (United States)
2. California Univ., San Diego, CA (United States)

We propose a new method of measuring the fast confined ct-particle distribution in a reacting plasma. The presence of ct-particles in a D-T plasma will create a high energy tail on the deuterium and tritium ion energy distributions. A 3.5 MeV alpha can transfer 3.4 MeV to a tritium ion in a single elastic scattering interaction. Calculations of the size of these knock-on tails in tokamaks such as TFTR, JET, and ITER show that it may be possible to measure these tails and provide information on the fast confined alphas. The knock-on tail ions will produce D-T neutrons with energies up to 20.7 MeV, so that D-T neutron spectroscopy can be used to monitor the alpha population. Neutron spectroscopy looks especially attractive for ITER. A collimated array of threshold neutron activation detectors could be used to deduce the confined alpha density profile. Tests of this diagnostic can also be done on TFTR and JET. Existing high energy neutral particle analyzers may allow observation of the ion tails directly via passive and/or active charge exchange.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG03-92ER54150; AC03-89ER51114
• OSTI ID: 10170299
• Report Number(s): GA-A--21715; CONF-940552--16; ON: DE94015856; BR: 35AT05000/AT0520210; 35AT10020/35KC07000
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700320
ALPHA PARTICLES
NEUTRON DETECTORS
NEUTRON SPECTROSCOPY
PLASMA DIAGNOSTIC TECHNIQUES AND INSTRUMENTATION
PLASMA DIAGNOSTICS
TOKAMAK DEVICES