A detailed investigation is made of the effect of finite confinement time and radial diffusion on the bum up of fusion produced 1 MeV tritons in hot deuterium plasmas. Explicit expressions are obtained for the concomitant reduction in total triton bum up and applications to JET and TFTR bum up measurements indicate diffusion constants D ≅ 0.1−0.2 m2/s for the fast tritons if the reduction is due to radial diffusion. The time dependence and the width of the emission profile of the 14 MeV neutrons from the triton bum up are also analyzed. Recent measurements of 14 MeV emission profiles on JET indicate a much smaller diffusion constant, viz. D ⪡ 0.1 m2/s. This implies that the observed finite confinement time of the tritons should not be due to radial diffusion and that the diffusion constant of the fast tritons should be very small. © 1992 IOP Published Ltd.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Mathematical Physics
- Condensed Matter Physics