UKAEA Journals

Showing 1 - 6 of 6 Journals Results
2015
CCFE-PR(15)101

Tokamaks are traditionally viewed as axisymmetric devices. However this is not always true, for example in the presence of saturated instabilities, error fields, or resonant magnetic perturbations (RMPs) applied for edge localized mode (ELM) control. We use the VMEC code (Hirshman and Whitson 1983 Phys. Fluids 26 3553) to …

Preprint Published
2014

It is known that magnetic perturbations can mitigate edge localized modes (ELMs) in experiments, for example, MAST [Kirk et al., Nucl. Fusion 53, 043007 (2013)]. One hypothesis is that the magnetic perturbations cause a three dimensional corrugation of the plasma and this corrugated plasma has different stability properties to peeling-ballooning mo…

Published
2010

In this work, the radial transport of tracers in an H-mode run in the CUTIE code [A. Thyagaraja et al. , Phys. Plasmas 12 , 090907 (2005)] is analyzed globally. Several techniques are applied to the study of the trajectories performed by the tracers, measuring the degree of self-similarity in the motion and searching for long range spatial and temp…

Published
2009

It has been suggested that radial transport in turbulent plasmas may be nonlocal and non-Markovian. In this paper the transport of test particles in the global, electromagnetic, three-dimensional code CUTIE [A. Thyagaraja and et al. , Phys. Plasmas 12 , 090907 (2005)] is characterized. This code includes a nonlinear feedback mechanism between the m…

Published
2008

The last flux surface can be used to identify the plasma configuration of discharges. For automated recognition of JET configurations, a learning system based on support vector machines has been developed. Each configuration is described by 12 geometrical parameters. A multiclass system has been developed by means of the one-versus-the-rest approac…

Published
2006

Radial profiles of the parallel-radial Reynolds stress component, proportional to the cross correlation between parallel and radial fluctuating velocities, have been measured in the plasma boundary region of the TJ-II stellarator. Experimental results show the existence of significant parallel turbulent forces at plasma densities above the threshol…

Published