Application of diffusion theory to the transport of neutral particles in fusion plasmas
It is shown that the widely held view that diffusion theory can not provide good accuracy for the transport of neutral particles in fusion plasmas is misplaced. In fact, it is shown that multigroup diffusion theory gives quite good accuracy as compared to the transport theory. The reasons for this are elaborated and some of the physical and theoretical reasons which make the multigroup diffusion theory provide good accuracy are explained. Energy dependence must be taken into consideration to obtain a realistic neutral atom distribution in fusion plasmas. There are two reasons for this; presence of either is enough to necessitate an energy dependent treatment. First, the plasma temperature varies spatially, and second, the ratio of charge-exchange to total plasma-neutral interaction cross section (c) is not close to one. A computer code to solve the one-dimensional multigroup diffusion theory in general geometry (slab, cylindrical and spherical) has been written for use on Cray computers, and its results are compared with those from the one-dimensional transport code ANISN to support the above finding. A fast, compact and versatile two-dimensional finite element multigroup diffusion theory code, FINAT, in X-Y and R-Z cylindrical/toroidal geometries has been written for use on CRAY computers. This code has been compared with the two dimensional transport code DOT-4.3. The accuracy is very good, and FENAT runs much faster compared even to DOT-4.3 which is a finite difference code.
- Research Organization:
- California Univ., Los Angeles (USA)
- OSTI ID:
- 5425177
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Two-dimensional finite element multigroup diffusion theory for neutral atom transport in plasmas
Application of diffusion theory to neutral atom transport in fusion plasmas
Related Subjects
DIFFUSION
MULTIGROUP THEORY
ACCURACY
PLASMA
NEUTRAL-PARTICLE TRANSPORT
ATOM TRANSPORT
COMPUTER CODES
CROSS SECTIONS
ENERGY DEPENDENCE
FINITE ELEMENT METHOD
ONE-DIMENSIONAL CALCULATIONS
TWO-DIMENSIONAL CALCULATIONS
NEUTRON TRANSPORT THEORY
NUMERICAL SOLUTION
RADIATION TRANSPORT
TRANSPORT THEORY
700105* - Fusion Energy- Plasma Research- Plasma Kinetics-Theoretical- (-1987)