Book/Report

FZJ-2018-03219

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Burn condition for fusion plasmas, helium particle confinement and exhaust efficiency : Orally presented at the 8th European Tokamak Programme Workshop, Gut Ising, December 13-15, 1989

Kever, H.FZJ* ; Reiter, D.FZJ* ; Wolf, G. H.FZJ*

1990
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/18712

Report No.: Juel-2342

Abstract: The burn condition for D-T plasmas is derived in a form which accounts for the stationary helium concentration being selfconsistently determined by the coupling of thefusion power and helium production. The ratio of the global $\alpha$-particle confinement time $\tau^{*}_{\alpha}$ (defintion in the text) to the energy confinement time $\tau_{E}$ is taken as a quantity characterizing the prevailing confinement arid exhaust regime. lt is shown that for an ignited and stationary burning D-T plasma this ratio needs to remain sufficiently below 15 (or below 10 for typical impurity concentrations). This poses a lower limit to the required helium exhaust efficiency and indieates that operational regimes might be desirable where the internal particle confinement time does not diverge too far from and in excess of the energy confinement time, and where the boundary layer - e.g. through high particle density and outward flow acts as a suffizient shield against recycled $\alpha$-particles. lt is further demonstrated that for any given temperature (and for otherwise equal overall exhaust and recycling conditions) either burning can be achieved at two quite different values of the fusion parameter (triple product n $\cdot$ T$\cdot$ r$_{E}$) and ash concentrations (one at Iow concentrations in the range 5 - 20 %, the other in the range of 20 - 35 %) or not at all. A similar evaluation applied to the D-$^{3}$He fusion reaction leads to even rnore stringent limits an the ratio $\tau^{*}_{\alpha}$/$\tau_{E}$, which must be smaller by a factor 3 to 4 compared to the D-T case.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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Database coverage:

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