Scaling of the Sawtooth Repetition Time from Simulations with Reduced Mhd Equations, and Comparison with Experiments in the Frascati Tokamak
نویسندگان
چکیده
The authors propose a scaling of the sawtooth repetition time for Ohmic discharges. This scaling has been obtained from simulations with reduced magnetohydrodynamic equations together with a simple profile consistent transport model. The choice of a profile consistent perpendicular thermal diffusion coefficient allows the scaling of the sawtooth repetition time to be obtained in terms of the diffusion coefficients and the safety factor at the edge, thus generalizing the scaling given by Vlad and Bondeson (Nucl. Fusion 29 (1989) 1139). The scaling is in good agreement with the experimental results for Ohmic discharges in the Frascati Tokamak.
منابع مشابه
Non-linear Mhd Studies in Toroidal Geometry - Disruptive Phenomena in Tokamak Plasmas*
NON-LINEAR MHD STUDIES IN TOROIDAL GEOMETRY DISRUPTIVE PHENOMENA IN TOKAMAK PLASMAS. Sawtooth oscillations and related fluid excitations are studied analytically and computationally, and some modifications relevant to high temperature regimes are presented. The role of the ideal kink in the sawtooth crash and a new theory of density limit disruptions are discussed. 1. NONLINEAR MHD STUDIES IN T...
متن کاملBOUT++: A framework for parallel plasma fluid simulations
A new modular code called BOUT++ is presented, which simulates 3D fluid equations in curvilinear coordinates. Although aimed at simulating Edge Localised Modes (ELMs) in tokamak x-point geometry, the code is able to simulate a wide range of fluid models (magnetised and unmagnetised) involving an arbitrary number of scalar and vector fields, in a wide range of geometries. Time evolution is fully...
متن کاملPossessions of viscous dissipation on radiative MHD heat and mass transfer flow of a micropolar fluid over a porous stretching sheet with chemical reaction
This article presents the heat and mass transfer characteristics of unsteady MHD flow of a viscous, incompressible and electrically conducting micropolar fluid in the presence of viscous dissipation and radiation over a porous stretching sheet with chemical reaction. The governing partial differential equations (PDEs) are reduced to ordinary differential equations (ODEs) by applying suitable si...
متن کاملComparative Study of Sawtooth Physics and Alfvén Waves via 2-D ECE Imaging on KSTAR, DIII-D, AUG and TEXTOR
High temporal and spatial resolution 2-D images of the sawtooth crash via the upgraded Electron Cyclotron Emission Imaging (ECEI) system on Toroidal EXperiment for Technology Oriented Research (TEXTOR) tokamak plasmas revealed new information concerning the sawtooth crash process. This includes: 1) observation of a wide range of crash time scales up to the resistive time scale 2) observation of...
متن کاملObservation of reversed shear Alfvén eigenmodes between sawtooth crashes in the Alcator C-Mod tokamak.
Groups of frequency chirping modes observed between sawtooth crashes in the Alcator C-Mod tokamak are interpreted as reversed shear Alfvén eigenmodes near the q=1 surface. These modes indicate that a reversed shear q profile is generated during the relaxation phase of the sawtooth cycle. Two important parameters, q_{min} and its radial position, are deduced from comparisons of measured density ...
متن کامل