On the interplay between plasma triangularity and micro-tearing turbulence

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In the foreseen upgrade of the Tokamak-a-Configuration-Variable (TCV) it is planned to add 3MW of additional RF power (3rd harmonic X-mode, X3, top-launch) to the present Electron Cyclotron (EC) system. With the upgrade of the EC-system, bringing the total EC power in X3-mode to 4.5MW, and the installation of 1 MW of neutral beam injection, a new avenue will be opened allowing the extensive study of H-mode physics in TCV. The envisaged new gyrotrons (lMW, 126GHz) are based on a minimum redesign of the 140 G

MAST plasmas with a safety factor above unity and a profile with either weakly reversed shear or broad low-shear regions, regularly exhibit long-lived saturated ideal magnetohydrodynamic (MHD) instabilities. The toroidal rotation is flattened in the presen ...

A new modular, digital, distributed feedback control system has been developed and installed to control the TCV plasma. With many more inputs and outputs, it provides the possibility to build control algorithms using far more information on the plasma state than previously possible as well as the ability to control many more actuators, including the multi-megawatt, multi-launcher electron cyclotron heating and current drive system. This paper provides an overview of the new control system, its integration i

In order to address non-local effects in turbulent transport of magnetic-fusion devices, the gyrokinetic code GENE has been extended from a flux tube to a more global geometry. This global version of GENE includes radial variations of temperature and density profiles, as well as of magnetic equilibrium quantities. Non-periodic radial boundary conditions allow for profile evolution. Thanks to an interface with the MHD equilibrium code CHEASE, as well as the implementation of various types of source and sink

Modulation of power amplitude is a widespread to determine the radial absorption profile of externally launched power in fusion plasmas. There are many techniques to analyze the plasma response to such a modulation. The break-in-slope (BIS) analysis can draw an estimated power deposition profile for each power step up. In this paper, the BIS analysis is used to monitor the power deposition location of one or two EC power beams simultaneously in a non-stationary plasma being displaced vertically in the TCV t

Heat loads on the JET MarkIIHD divertor are measured by IR thermography in high triangularity plasmas with edge conditions of advanced tokamak scenarios (AT). AT scenarios operate at low density (n(e,av) < 5 x 10(19) m(-3) at JET) to maximise the non inductive current drive, leading to high target temperature (20 < T-e < 40 eV), hence high heat loads. Comparisons with a typical baseline inductive scenario (n(e,av) similar or equal to 10 x 10(19) m(-3)), show that for similar input power (similar or equal to

The development of reliable H-modes on MAST, together with advances in heating power and a range of high spatial resolution diagnostics, has provided a platform to enable MAST to address some of the most important issues of tokamak stability. In particular the high beta potential of the spherical tokamak is highlighted with stable operation at beta(N) similar to 5-6, beta(T) similar to 16% and beta(p) up to similar to2. Magnetic diagnostic evaluation of the global beta parameters is independently confirmed

We have investigated the effect of different ion cyclotron resonance frequency (ICRF) heating schemes, of error field modes, of the plasma shape and edge magnetic shear, and of the ion delB drift direction on the stability of Alfven eigenmodes (AEs). The use of multi-frequency or 2nd harmonic minority ICRF heating at high plasma density gives rise to a lower fast ion pressure gradient in the plasma core and to a reduced mode activity in the Alfven frequency range. Externally excited low-amplitude error fiel

The particle confinement in a magnetized plasma torus with superimposed vertical magnetic field is modeled and measured experimentally. The formation of an equilibrium characterized by a parallel plasma current canceling out the grad B and curvature drifts is described using a two-fluid model. Characteristic response frequencies and relaxation rates are calculated. The predictions for the particle confinement time as a function of the vertical magnetic field are verified in a systematic experimental study o

In this paper the effects of the magnetic self-field on the transport properties of a multi-layer high-Tc superconducting (HTS) cable are investigated by means of 2D finite element method (FEM) simulations. Analyzed is a 3-layer HTS cable, but the developed methods can be used for a different number of layers. The superconductor is described by the non-linear power-law relation E=Ec(J/Jc)^n, where the parameters Jc and n depend on the magnetic field experienced by the material. This dependence decreases the

We study the dynamic motion of magnetic structures composed of micron-size ferromagnetic particles. The supraparticle structures are retained in a microfluidic channel by a local oscillating magnetic field while subjected to a viscous liquid flow. We analyze the position of the magnetic structures as a function of the flow velocity and of the frequency and amplitude of the magnetic field. We also study the conditions for release of the magnetic structures from the localized magnetic field region.

In small area capacitive reactors, the rf and dc components of the plasma potential can be assumed to be uniform over all the plasma bulk because of the low plasma resistivity. In large area reactors, however, the rf plasma potential can vary over a long range across the reactor due to rf current flow and the nonzero plasma impedance. A perturbation in rf plasma potential, due to electrode edge asymmetry or the boundary of a dielectric substrate, propagates along the resistive plasma between capacitive shea

On the interplay between plasma triangularity and micro-tearing turbulence

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Millimeter Wave System Upgrades On TCV: Additional X3 Power And Fast ECE Polarizers

Saturated ideal modes in advanced tokamak regimes in MAST

Architecture and commissioning of the TCV distributed feedback control system

Development of a Global Version of the Gyrokinetic Microturbulence Code GENE

Simultaneous Power Deposition Detection of Two EC Beams with the BIS Analysis in Moving TCV Plasmas

Divertor heat load in ITER-like advanced tokamak scenarios on JET

Stability at high performance in the MAST spherical tokamak

Alfven mode stability and wave-particle interaction in the JET tokamak: prospects for scenario development and control schemes in burning plasma experiments

Effects of a vertical magnetic field on particle confinement in a magnetized plasma torus

Numerical Analysis of the Effects of the Magnetic Self-Field on the Transport Properties of a Multilayer HTS Cable

Dynamics of magnetically retained supraparticle structures in a liquid flow

Nonuniform radio-frequency plasma potential due to edge asymmetry in large-area radio-frequency reactors