Open AccessEconomic analyses of alpha channeling in tokamak power plants.
Author(s) -
D.A. Ehst
Publication year - 1998
Language(s) - English
Resource type - Reports
DOI - 10.2172/12061
Subject(s) - tokamak , bootstrap current , electron , plasma , atomic physics , physics , nuclear engineering , alpha particle , toroid , fusion power , power (physics) , beta (programming language) , steady state (chemistry) , ion , nuclear physics , computational physics , chemistry , computer science , engineering , thermodynamics , quantum mechanics , programming language
The hot-ion-mode of operation [1] has long been thought to offer optimized performance for long-pulse or steady-state magnetic fusion power plants. This concept was revived in recent years when theoretical considerations suggested that nonthermal fusion alpha particles could be made to channel their power density preferentially to the fuel ions [2,3]. This so-called anomalous alpha particle slowing down can create plasmas with fuel ion temperate T{sub i} somewhat larger than the electron temperature T{sub e}, which puts more of the beta-limited plasma pressure into the useful fuel species (rather than non-reacting electrons). As we show here, this perceived benefit may be negligible or nonexistent for tokamaks with steady state current drive. It has likewise been argued [2,3] that alpha channeling could be arranged such that little or no external power would be needed to generate the steady state toroidal current. Under optimistic assumptions we show that such alpha-channeling current drive would moderately improve the economic performance of a first stability tokamak like ARIES-I [4], however a reversed-shear (advanced equilibrium) tokamak would likely not benefit since traditional radio-wave (rf) electron-heating current drive power would already be quite small