In this paper the diffusion of guiding centers induced by stochastic magnetic and electric field fluctuations, with both time and space dependence, is analyzed for the case of tokamak plasmas. General experimental results on tokamak fluctuations are used to derive guidingcenter equations that properly describe the particle motion. These equations assume uniform average magnetic and electric fie...

Electron cyclotron resonance heating and electron cyclotron current drive, disruptive events, and sawtooth activity are all known to produce suprathermal electrons in fusion devices, motivating increasingly detailed studies of the generation and dynamics of this suprathermal population. Measurements have been performed in the past years in the tokamak a configuration variable (TCV) tokamak usin...

To step up from current day fusion experiments to power producing fusion reactors, it is necessary to control long pulse, burning plasmas. Stability and confinement properties of tokamak fusion reactors are determined by the current or q profile. In order to control the q profile, it is necessary to measure it in real-time. A real-time motional Stark effect diagnostic is being developed at Kore...

The use of lower hybrid waves for current drive in steady state tokamak power reactors is studied. Constraints imposed by rf wave propagation are considered in detail. The effect of decoupling of electron and ion temperatures is studied and is found to enhance significantly the ratio of fusion power to dissipated power. Tradeoffs for parameters of rf driven steady state reactors are determined....

Recently a number of major, unanticipated effects have been reported in tokamak edge research raising the question of whether we understand the controlling physics of the edge. This report is on the first part – here focused on the outer divertor – of a systematic study of the simplest possible edge plasma – no ELMs, no detachment, etc. – for a set of 10 repeat, highlydiagnosed, single-null, di...

A simple unified model of intrinsic rotation and momentum transport in high confinement regime H-mode tokamak plasmas is presented. Motivated by the common dynamics of the onset of intrinsic rotation and the L-H transition, this simple model combines E B shear-driven residual stress in the pedestal with a turbulent equipartition pinch to yield rotation profiles. The residual stress is the prima...

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...

Dynamics of ion internal transport barrier (ITB) formation and impurity transport both in the Large Helical Device (LHD) heliotron and JT-60U tokamak are described. Significant differences between heliotron and tokamak plasmas are observed. The location of the ITB moves outward during the ITB formation regardless of the sign of magnetic shear in JT-60U and the ITB becomes more localized in the ...

Introduction Filaments, or blobs, are field aligned plasma structures which have been observed in the scrape of layer of magnetically confined plasmas. These filaments carry particles into the SOL and therefore play a role in determining the profiles during L-mode and inter-ELM H-mode scenarios. While there have been many investigations into the dynamics of such filaments [1, 2], few have conce...

An important milestone on the Fast Track path to Fusion Power is to demonstrate reliable commercial application of Fusion as soon as possible. Many applications of fusion, other than electricity production, have already been studied in some depth for ITER class facilities. We show that these applications might be usefully realized on a small scale, in a Multi-Functional Compact Tokamak Reactor ...