Aspects of trapped confined alpha physics on TFTR

Conference · Sat Jun 01 04:00:00 EDT 1996

OSTI ID:251427

Petrov, M P ^[1]; Gorelenkov, N N ^[2]; Budny, R V; Mansfield, D K; Medley, S S ^[3]; Duong, H H; Fisher, R K; McChesney, J M; Parks, P B ^[4]

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1. A.F. Ioffe Physical-Technical Inst., St. Petersburg (Russian Federation)
2. TRINITI, Troitsk (Russian Federation)
3. Princeton Univ., NJ (United States). Plasma Physics Lab.
4. General Atomics, San Diego, CA (United States)

The energy distributions and radial density profiles of the fast-confined trapped alpha particles in DT experiments on TFTR are being measured in the energy range 0.5 to 3.5 MeV using the Pellet Charge Exchange diagnostic developed in a collaboration involving General Atomics, the A.F. Ioffe Physical-Technical Institute, and the Princeton Plasma Physics Laboratory. A brief description of the measurement technique which involves active neutral particle analysis using the ablation cloud surrounding an injected lithium or pellet as the neutralizer is presented. In the core of quiescent TFTR discharges, measured alpha spectra are consistent with classical slowing down. Measured Doppler broadening of alphas near the birth energy is consistent with the effective temperature of interacting deuterium and tritium ions. Outside the core alpha energy spectra and density profiles are influenced by the magnetic field ripple and appear to be consistent with stochastic ripple diffusion. Sawtooth oscillations lead to the significant broadening of alpha density profiles. The experimental data are modeled using a Fokker-Planck Post TRANSP (FTTP) code which includes the effects of the classical slowing down, magnetic field ripple losses, and the sawtooth mixing of alpha particles. The comparison of the experimental data with the FPPT calculations shows that broadening of trapped alpha density profiles after the sawtooth crashes can be explained by the influence of poloidal electric field generated during the crashes.

• Research Organization: General Atomics, San Diego, CA (United States); Princeton Univ., NJ (United States). Plasma Physics Lab.
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG03-92ER54150; AC02-76CH03073
• OSTI ID: 251427
• Report Number(s): GA-A--22323; CONF-9606226--1; ON: DE96011551
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALPHA PARTICLES
CHARGE EXCHANGE
CONFINEMENT
ENERGY SPECTRA
ION DENSITY
PARTICLE LOSSES
PELLET INJECTION
PLASMA DIAGNOSTICS
TFTR TOKAMAK