A parameter-free limiting technique is developed for high-order unstructured-grid methods to capture discontinuities when solving hyperbolic conservation laws. The technique is based on a “troubled-cell” approach, in which cells requiring limiting are first marked, and then a limiter is applied to these marked cells. A parameter-free accuracypreserving TVD marker based on the cell-averaged solu...

The two-dimensional multifluid code TECXY has been used to model the biasing (with respect to the first wall) of the toroidal belt limiter ALT-II on the tokamak TEXTOR-94 and of the new toroidal pump limiter being installed on Tore Supra tokamak in the framework of the CIEL project. It is well known that the edge flow pattern can be influenced by the poloidal electric drifts from imposing radia...

Measurements of fast phenomena in the vicinity of a limiter inserted into a linear plasma column are shown in this work. The results were conducted at the plasma generator PSI-2 (Humboldt Universitaet zu Berlin, Germany) which provides a stationary plasma produced in a DC arc discharge. The plasma near a tungsten limiter was imaged on a photomultiplier tube equipped with 16 anodes. The photomul...

Abstract. This paper develops Runge-Kutta PK-based central discontinuous Galerkin (CDG) methods with WENO limiter to the oneand two-dimensional special relativistic hydrodynamical (RHD) equations, K = 1,2,3. Different from the non-central DG methods, the Runge-Kutta CDG methods have to find two approximate solutions defined on mutually dual meshes. For each mesh, the CDG approximate solutions o...

We consider finite volume methods for the numerical solution of conservation laws. In order to achieve high-order accurate numerical approximation to non-linear smooth functions, we introduce a new class of limiter functions for the spatial reconstruction of hyperbolic equations. We therefore employ and generalize the idea of double-logarithmic reconstruction of Artebrant and Schroll [R. Artebr...

EFFECT OF THE SELF-PUMPED LIMITER CONCEPT ON THE TRITIUM FUEL CYCLE P. A. Finn, D. K. Sze and A. Hassanein Argonne National Laboratory Argonne, I I 60439 ABSTRACT The self-pumped limiter concept for impurity control of the plasma of a fusion reactor has a major impact on the design of the tritium systems. To achieve a sustained burn, conventional limiters and divertors remove large quantities o...

Fusion first walls are subject to a large number of possible failure mechanisms, including erosion due to sputtering, arcing, blistering and vaporization and crack growth due to thermal and magnetic stresses. Each of these failure mechanisms is poorly characterized and has the potential of being severe. A strategy for designing reliably in the face of great uncertainty is discussed. Topological...

Confinement scalings of divertor and radiofrequency heated discharges are shown to differ significantly from the standard neutral beam heated limiter scaling. The random coefficient two stage regression algorithm is applied to a neutral beam heated limiter subset of the ITER L mode database as well as a combined dataset. We find a scaling similar to Goldston scaling for the NB limiter dataset a...

Abs t rac t For a clipped channel with a Gaussian input, a predistortionlrestoration technique to reduce clipping-induced nonlinear distortion is proposed and analyzed. The input signal is processed by a nonlinear predistorter circuit, reducing the probability of clipping. The receiver output signal passes through a restorer having the inverse transfer characteristic, which yields the original ...