High field side measurements of non-thermal electron cyclotron emission on TCV plasmas with ECH and ECCD

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Efficient, real-time and unsupervised data analysis is one of the key elements for achieving scientific success in complex engineering and physical systems, of which three examples are the currently operating Joint European Torus (JET) and the soon-to-be-built International Thermonuclear Experimental Reactor (ITER) and the Square Kilometre Array (SKA) telescope. There is a wealth of signal processing techniques that are being applied to data analysis in such complex systems, and here we wish to present some

We investigate suprathermal ion dynamics in simple magnetized toroidal plasmas in the presence of electrostatic turbulence driven by the ideal interchange instability. Turbulent fields from fluid simulations are used in the nonrelativistic equation of ion motion to compute suprathermal tracer ion trajectories. Suprathermal ion dispersion starts with a brief ballistic phase, during which particles do not interact with the plasma, followed by a turbulence interaction phase. In this one simple system, we obser

Intermittent blobs, which propagate across a confining magnetic fields, are universally observed in natural and laboratory plasmas. In fusion plasmas, cross-field transport of particles and energy are associated, at least in part, with the propagation of blobs, which are therefore of great importance for the design of future fusion reactors. In TORPEX, blobs are generated from ideal interchange modes and, driven by B and curvature-induced charge separation, propagate radially outwards. An analytical blob s

This paper reports the results of recent experiments performed on the JET tokamak on Alfven Eigenmodes (AEs) with toroidal mode number (n) in the range n=3-15. The stability properties and the use of these medium-n AEs for diagnostic purposes is investigated experimentally using a new set of compact in-vessel antennas, providing a direct and real-time measurement of the frequency, damping rate and amplitude for each individual toroidal mode number. First, we report on the development of a new algorithm for

The goal of the present diploma work is to experimentally investigate the fast ion physics in TORPEX plasmas, in which interchange modes with flute characteristics and intermittent transport events, i.e. blobs, are observed to dominate the plasma dynamics. During the first part of the diploma, the Candidate will test different fast ion emitters on a test bench, which will be then mounted into the BN casing to form the fast ion source. In parallel, the Candidate will design an innovative in-vessel movable sy

The TORoidal Plasma EXperiment (TORPEX) at CRPP generates and confines plasmas in a magnetic configuration with open helical magnetic field lines, in which similarly to the SOL of magnetic fusion devices, grad B and magnetic field curvature are at play. In the high vertical magnetic field, Bz, scenario, interchange modes are observed with flute characteristics, k// = 0, and a global character in the perpendicular direction, growing on the largest allowed spatial scale. By further increasing Bz, sheath effec

We review recent results on wafer fused long wavelength VCSELs emitting in the 1310 - 2000 nm range. This technology allows reaching fundamental mode output in excess of 4.5 mW at room temperature and close to 3 mW at 70 degrees C for both the 1310 nm and 1550 nm wavebands-the highest values obtained so far. Emission wavelength can be tuned continuously with current with a tuning range as large as 15 nm. For 2000 nm emission wavelength, room temperature output is similar to 0.5 mW, limited so far by high op

The unique flexibility of TCV in plasma shaping has been exploited to address different aspects of tokamak physics in which the plasma shape may play a role. This paper summarizes the experiments undertaken in the TCV tokamak ("Tokamak à Configuration Variable") over the last decade in stability and transport and offers a comprehensive and integrated view of the various effects of plasma shape observed. For each of these effects, the relation between experimental results and theoretical predictions is stres

A key issue for steady-state tokamak operation is to determine the edge conditions that are compatible both with good core confinement and with the power handling and plasma exhaust capabilities of the plasma facing components (PFCs) and divertor systems. A quantitative response to this open question will provide a robust scientific basis for reliable extrapolation of present regimes to an ITER compatible steady-state scenario. In this context, the JET programme addressing steady-state operation is focused

ASDEX Upgrade has recently finished its transition towards an all-W divertor tokamak, by the exchange of the last remaining graphite tiles to W-coated ones. The plasma start-up was performed without prior boronization. It was found that the large He content in the plasma, resulting from DC glow discharges for conditioning, leads to a confinement reduction. After the change to D glow for inter-shot conditioning, the He content quickly dropped and, in parallel, the usual H-Mode confinement with H factors clos

This paper presents a feasibility study for a motional Stark effect (MSE) [F. M. Levinton , Phys. Rev. Lett. 63, 2060 (1989)] diagnostic on the TCV tokamak. A numerical simulation code has been used to identify the optimal port arrangement and geometrical layout. It predicts the expected measurement accuracy for a range of typical plasma scenarios. With the existing neutral beam injector (NBI) and a detection system based on current day technology, it should be possible to determine the safety factor with a

Current profile tailoring has been performed by application of electron cyclotron heating (ECH) and electron cyclotron current drive, leading to improved energy confinement in the plasma core of the TCV tokamak. The improved confinement is characterized by a substantial enhancement (H-factor) of the global electron energy confinement time relative to the prediction of the RLW scaling law (Rebut P H et al 1989 Proc. 12th Int. Conf. of Plasma Physics and Controlled Fusion Research (Nice, 1988) vol 2 (Vienna:

High field side measurements of non-thermal electron cyclotron emission on TCV plasmas with ECH and ECCD

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From astrophysics to fusion plasmas: signal processing and system optimization analysis for ITER

Nondiffusive Suprathermal Ion Transport in Simple Magnetized Toroidal Plasmas

Understanding and taming plasma blobs in toroidal magnetized plasmas

Recent JET Experiments on Alfven Eigenmodes with Intermediate Toroidal Mode Numbers: Measurements and Modelling

Experimental investigation of fast ion dynamics in TORPEX toroidal plasmas

Investigation of sheath effects on interchange modes in TORPEX plasmas

Recent Developments in Long Wavelength VCSELs Based on Localized Wafer Fusion

Physics Insight and Performance Benefit from Plasma Shaping Experiments in MHD and Energy Transport in the TCV Tokamak

Development of steady-state scenarios compatible with ITER-like wall conditions

Plasma wall interaction and its implication in an all tungsten divertor tokamak

Feasibility of a motional Stark effect system on the TCV tokamak

Control of electron internal transport barriers in TCV