Frederick Alan Kelly

Impurity seeded radiative power exhaust solutions for ITER

The injection of impurities into the scrape-off layer (SOL) to stimulate radiative power exhaust from the mantle and SOL/divertor of the International Thermonuclear Experimental Reactor (ITER) is investigated. Intermediate Z impurities (e.g. argon to krypton) are able to radiate more than two thirds of the plasma heating power, without significant effect on the plasma power balance or the shear profile and without triggering an H to L mode transition

Robustness of radiative mantle plasma power exhaust solutions for ITER

The robustness of impurity seeded radiative mantle plasma power exhaust solutions for the ITER ignited operating point to uncertainties in the energy and impurity transport and in several physics and operating parameters is examined. Our results indicate that ~70 to 95% of the input power can be radiated from inside the separatrix with neon, argon or krypton injection, without significant detriment to the core power balance or collapse of the radial temperature profile, for a wide range of values of the impurity pinch velocity, the edge temperature pedestal and the plasma density, and for a variety of different energy and impurity transport models. Auxiliary power is used to compensate for central radiative losses. Similar radiative power exhaust solutions are identified for a possible ignited ITER operating point at the Greenwald density limit

Thermal instability theory analysis of multifaceted asymmetric radiation from the edge (MARFE) in Tokamak Experiment for Technology Oriented Research (TEXTOR)

The density limits for a series of shots in TEXTOR [Tokamak Experiment for Technology Oriented Research, E. Hintz, P. Bogen, H. A. Claasen et al., in Contributions to High-Temperature Plasma Physics, edited by K. H. Spatschek and J. Uhlenbusch (Akademie Verlag, Berlin, 1994, p. 373)], over a range of heating powers, that ended in multifaceted asymmetric radiation from the edge (MARFE) have been analyzed within the context of thermal instability theory. The prediction of MARFE onset agrees with observation to within the experimental uncertainty.

Parametric dependence of density limits in the Tokamak Experiment for Technology Oriented Research (TEXTOR): Comparison of thermal instability theory with experiment

The observed dependence of the TEXTOR [Tokamak Experiment for Technology Oriented Research: E. Hintz, P. Bogen, H. A. Claassen et al., Contributions to High Temperature Plasma Physics, edited by K. H. Spatschek and J. Uhlenbusch (Akademie Verlag, Berlin, 1994), p. 373] density limit on global parameters (I, B, P, etc.) and wall conditioning is compared with the predicted density limit parametric scaling of thermal instability theory. It is necessary first to relate the edge parameters of the thermal instability theory to n and the other global parameters. The observed parametric dependence of the density limit in TEXTOR is generally consistent with the predicted density limit scaling of thermal instability theory. The observed wall conditioning dependence of the density limit can be reconciled with the theory in terms of the radiative emissivity temperature dependence of different impurities in the plasma edge. The thermal instability theory also provides an explanation of why symmetric detachment preced...