Studies of energetic confined alphas using the pellet charge exchange diadgnostic on TFTR

Technical Report · Sat Jul 01 04:00:00 EDT 1995

DOI:https://doi.org/10.2172/93655· OSTI ID:93655

Petrov, M P ^[1]; Budny, R V ^[2]; Duong, H H ^[3]

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1. AN SSSR, Leningrad (Russian Federation). Fiziko-Tekhnicheskij Inst.
2. Princeton Univ., NJ (United States). Plasma Physics Lab.
3. General Atomics, San Diego, CA (United States)

Results from recent DT experiments on TFIR to measure the energy distribution and radial density profile of fast confined alphas with the use of Li pellets and neutral particle analysis are presented. When a pellet is injected into the plasma, a toroidally extended ablation cloud is formed that travels with the pellet. A small fraction of the fusion alphas incident on the cloud are converted to helium neutrals as a result of electron capture processes. The escaping energetic helium neutrals are analyzed and detected by the neutral particle analyzer. Radially resolved energy spectra of trapped confined alphas in 0.5-2 MeV range and radial alpha density profiles are presented in this paper. The experimental data are compared with modeling results obtained with the TRANSP Monte-Carlo Code and with a specially developed Fokker-Planck Post Processor (FPP) that uses the alpha source distribution produced by TRANSP. Comparison of the experimental data with TRANSP and FPP show that the alphas in the plasma core of sawtooth free discharges in TFIR are well confined and slow down classically. The energy and radial profiles distributions outside the plasma core show the influence of stochastic ripple losses on alphas. Measurements for sawtoothing plasmas show a significant outward radial transport of trapped alphas.

• Research Organization: Princeton Univ., NJ (United States). Plasma Physics Lab.
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 93655
• Report Number(s): PPPL--3121; ON: DE95016255
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALPHA PARTICLES
CONFINEMENT TIME
ENERGY SPECTRA
LITHIUM
PELLET INJECTION
PLASMA DIAGNOSTICS
TFTR TOKAMAK