Publications by Richard Pitts | EPFL Graph Search

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Geodesic acoustic modes (GAMs) may generate strong oscillations in the radial electric field and therefore are considered as a possible trigger mechanism for the L-H transition. This contribution focuses on the characterization of GAMs in JET plasmas when ...

New experimental results on transient loads during ELMs and disruptions in present divertor tokamaks are described and used to carry out a extrapolation to ITER reference conditions and to draw consequences for its operation. In particular, the achievement ...

Using infra-red (IR) thermography, power loads onto the MKII Gas-Box divertor targets have been investigated in Type-I ELMy H-Mode plasmas at JET in medium current discharges (I-p = 2.6MA and B-T = 2.7 T). Heat fluxes are calculated from the measured diver ...

There is an increasing body of evidence that the energy lost from diverted tokamak plasmas due to edge localized mode (ELM) activity may not be confined solely to deposition on divertor components. Plasma-facing surfaces in the main confinement chamber als ...

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

Starting from a standard single null X-point configuration, a second order null divertor (snowflake (SF)) has been successfully created on the Tokamak a Configuration Variable (TCV) tokamak. The magnetic properties of this innovative configuration have been analysed and compared with a standard X-point configuration. For the SF divertor, the connection length and the flux expansion close to the separatrix exceed those of the standard X-point by more than a factor of 2. The magnetic shear in the plasma edge

A new compact gamma-ray spectrometer was developed in order to optimise the measurement of bremsstrahlung radiation emitted from runaway electrons in the MeV range. The detector is based on a cerium doped lutetium-yttrium oxyorthosilicate (LYSO:Ce) scintil ...

This report summarizes Type I edge localized mode (ELM) dynamics measurements from a number of tokamaks, including ASDEX-Upgrade, DIII-D, JET, JT-60U and MAST, with the goal of providing guidance and insight for the development of ELM simulation and modell ...

Alfven eigenmodes (AEs) are routinely seen in present-day tokamaks and stellarators with energetic particles and they represent an attractive form of MHD spectroscopy that provides valuable information on background plasma and on the energetic particles. P ...

Particle flow measurements parallel to the total magnetic field direction have been obtained for the first time in the TCV tokamak scrape-off layer. The plasma shape flexibility of TCV, coupled with carefully matched ohmic diverted discharges in forward an ...

The kinetic code for plasma periphery (KIPP) was used to assess the importance of the kinetic effects of parallel electron transport in the scrape-off layer (SOL) and divertor of JET high radiative H-mode inter-ELM plasma conditions with the ITER-like wall ...

Fast ions have recently been found to significantly impact and partially suppress plasma turbulence both in experimental and numerical studies in a number of scenarios. Understanding the underlying physics and identifying the range of their beneficial effe ...

A number of codes are in use at JET to model the edge plasma. The range of edge codes is described as is the range of physics issues being explored by these codes. The balance between focussed modelling (that looking at particular physics effects) and integrated modelling (attempting to combine codes or encapsulate the physics from some codes into other codes) is examined. (C) 2003 Elsevier Science B.V. All rights reserved.

The paper is dedicated to the characterisation of multi-strap ICRH antenna coupling to plasma. Relevance of traditional concept of coupling resistance to antennas with mutually coupled straps is revised and the importance of antenna port excitation consist ...

This paper presents the first application to real JET data of the new equilibrium code NICE which enables the consistent resolution of the inverse equilibrium reconstruction problem in the framework of non-linear free-boundary equilibrium coupled to the St ...

Total radiative powers measured by AXUV diode based bolometer cameras have been measured in lower single null, third harmonic electron cyclotron resonance (X3 ECR) heated TCV ELMing H-mode discharges. Although, the non-flat spectral response of the diodes means that total radiated powers can be in error by as much as a factor 2, with time resolution on the order of several microseconds, the cameras can resolve plasma radiation dynamics on the ELM timescale. Observations show that: (i) most of the radiation

Reliable algorithms for disruption avoidance and prediction are foreseen to play a fundamental role in the JET control system for the successful operation of the machine in the upcoming deuterium-tritium campaigns. The integration of such algorithms is exp ...

The production cross section of a top quark pair in association with a photon is measured in proton-proton collisions in the decay channel with two oppositely charged leptons (e(+/-)mu(-/+), e(+)e(-), or mu(+)mu(-)). The measurement is performed using 138 ...

The electron temperature and density pedestals tend to vary in their relative radial positions, as observed in DIII-D (Beurskens et al 2011 Phys. Plasmas 18 056120) and ASDEX Upgrade (Dunne et al 2017 Plasma Phys. Control. Fusion 59 14017). This so-called ...

Experimental observations and some preliminary results from B2-Eirene code modelling of divertor detachment in the TCV tokamak are reported, with emphasis on the aspects of this detachment related to divertor geometry. The contribution is restricted to deuterium fuelled ohmic plasmas for which the CB drift is directed away from the X-point of lower single-null, open diverted equilibria with fixed elongation and triangularity. Unlike more conventional diverted equilibria, however, the configurations describe

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Geodesic acoustic mode evolution in L-mode approaching the L-H transition on JET

Transient heat loads in current fusion experiments, extrapolation to ITER and consequences for its operation

ELM resolved energy distribution studies in the JET MKII Gas-Box divertor using infra-red thermography

Far SOL ELM ion energies in JET

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

Snowflake Divertor Plasmas on TCV

Development of a new compact gamma-ray spectrometer optimised for runaway electron measurements

Survey of Type I ELM dynamics measurements

MHD spectroscopy of JET plasmas with pellets via Alfven eigenmodes

Parallel SOL flow on TCV

Assessment of the strength of kinetic effects of parallel electron transport in the SOL and divertor of JET high radiative H-mode plasmas using EDGE2D-EIRENE and KIPP codes

Non-Maxwellian fast particle effects in gyrokinetic GENE simulations

An overview of JET edge modelling activities

ICRH antenna &ITS&IT-matrix measurements and plasma coupling characterisation at JET

Equilibrium reconstruction at JET using Stokes model for polarimetry

Fast radiation dynamics during ELMs on TCV

A First Analysis of JET Plasma Profile-Based Indicators for Disruption Prediction and Avoidance

Measurement of the inclusive and differential t(t)over-bar gamma cross sections in the dilepton channel and effective field theory interpretation in proton-proton collisions at root s=13 TeV

Effect of the relative shift between the electron density and temperature pedestal position on the pedestal stability in JET-ILW and comparison with JET-C

Divertor geometry effects on detachment in TCV