Measurements of charged-fusion-product diffusion in TFTR
The single particle confinement of charged fusion products, namely the 1 MeV triton and the 3 MeV proton, has been studied using a detector located near the outer midplane of TFTR. The detector, which measures the flux of escaping particles, is composed of a scintillator (ZnS(Ag)) and a system of collimating apertures, which permit pitch angle, energy and time resolution. Measurements indicate a level of losses higher than expected from a first-orbit loss mechanism alone. The primary candidate for explaining the observed anomalous losses is the toroidal field (TF) stochastic ripple diffusion, theoretically discovered by Goldston, White and Boozer. This loss mechanism is expected to be localized near the outer midplane where, at least at high current ({approx lt} 1.0 MA), it would locally dominate over first-orbit losses. Calculations made with a mapping particle orbit code (MAPLOS) show a semi-quantitative agreement with the measurements. The predominant uncertainties in the numerical simulations were found to originate from the modeling of the first wall geometry and also from the assumed plasma current and source profiles. Direct measurements of the diffusion rate were performed by shadowing the detector with a second movable probe used as an obstacle. The diffusion rate was also measured by moving the detector behind the radius of the RF limiters, located on the outer wall. Comparisons of these experimental results with numerical simulations, which include diffusive mechanisms, indicate a quantitative agreement with the TF stochastic ripple diffusion model.
- Research Organization:
- Princeton Univ., NJ (United States)
- OSTI ID:
- 5222766
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PROTONS
DIFFUSION
TFTR TOKAMAK
CHARGED-PARTICLE TRANSPORT
TRITONS
COMPARATIVE EVALUATIONS
CONFINEMENT
FIRST WALL
FUSION YIELD
M CODES
MAGNETIC FIELDS
MATHEMATICAL MODELS
MEV RANGE 01-10
ORBITS
PLASMA SIMULATION
STOCHASTIC PROCESSES
VACUUM SYSTEMS
BARYONS
CHARGED PARTICLES
CLOSED PLASMA DEVICES
COMPUTER CODES
ELEMENTARY PARTICLES
ENERGY RANGE
EVALUATION
FERMIONS
HADRONS
MEV RANGE
NUCLEAR REACTION YIELD
NUCLEONS
RADIATION TRANSPORT
SIMULATION
THERMONUCLEAR DEVICES
THERMONUCLEAR REACTOR WALLS
TOKAMAK DEVICES
YIELDS
700330* - Plasma Kinetics
Transport
& Impurities- (1992-)