Gyrokinetic investigation of magnetic islands in tokamaks

Abstract

A powerful new numerical tool to carry out investigations into magnetic islands by means of the gyrokinetic equations is described in the present paper. An island structure, with imposed width and rotation, has been implemented in the flux-tube code GKW. Numerical simulations retaining finite Larmor radius effects (FLRs), toroidicity, kinetic electrons and self-consistent electrostatic potential are presented, concerning, among others, the incomplete density profile flattening for small magnetic islands, the dependency of the island potential on the island rotation frequency and the emission of drift waves connected to the island rotation. Turbulent fluctuations are not fully resolved by filtering out short wavelengths. © 2010 IOP Publishing Ltd.