Publications de Jean-Marc Moret

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The ITER high-frequency (HF) magnetic diagnostic system has to provide essential measurements of MHD instabilities with |deltaBmeas/BPOL|~1e-4 (~1G) for frequencies up to 2MHz to resolve toroidal mode numbers (n) in the range |n|=10 to |n|=50. A review of ...

Within the 9th European Framework programme, since 2021 EUROfusion is operating five tokamaks under the auspices of a single Task Force called ‘Tokamak Exploitation’. The goal is to benefit from the complementary capabilities of each machine in a coordinat ...

A large variety of plasma conditions has been created in TCV (Tokamak a Configuration Variable, B-T < 1.5 T, R-0 = 0.88 m, a < 0.25 m). They include limited and diverted discharges with elongations in the range 1-2.58, triangularities between -0.7 and 1 as well as 'square' shapes with plasma currents in the range 0.1-1 MA. Over the entire range of quasi-stationary ohmic conditions investigated we observe a correlation between electron pressure profiles and conductivity profiles, suggesting that [p]/p(0) app

The upgrade project for TCV (Tokamak à Configuration Variable) includes the installation of a set of saddle coils, namely the saddle coil system (SCS), located and powered such as to create a helical magnetic perturbation. Using independent power supplies, ...

During the first two years of operation, the TCV tokamak has produced a large variety of plasma shapes and magnetic configurations, with 1.0 less than or equal to B-tor less than or equal to 1.46T, I-p less than or equal to 800kA, kappa less than or equal to 2.05, -0.7 less than or equal to delta less than or equal to 1. A new shape control algorithm, based on a finite element reconstruction of the plasma current in real time, has been implemented. Vertical growth rates up to 1000 s(-1) have been stabilized

Results from the first experiments to drive Alfven Eigenmodes (AEs) with antennas external to a tokamak plasma are presented. In ohmically heated plasma discharges, direct experimental measurements of the damping of toroidicity induced AEs (TAEs) have allowed an identification of different regimes corresponding to different dominant TAE absorption mechanisms with a wide range of damping rates, 10(-3) less than or equal to gamma/omega less than or equal to 10(-1). In plasmas heated by ion cyclotron resonance

A high performance system, specially designed for real-time plasma control and event detection on fusion experiments has been developed by the Centro de Fusao Nuclear of the Instituto Superior Tecnico (CFN/IST). Presently it is being integrated into the ad ...

An analysis of the effect of magnetic geometry on heat flux in a wide range of single null diverted discharge configurations with 1.5 < κ(95) < 2.2, 0.2 < δ(95) < 0.45 suggests that elongation is beneficial for confinement. If heat diffusivities are assumed not to depend on plasma shape., the predicted exponent for a power law scaling with elongation is alpha(kappa) approximate to 0.74, based on the configurations in the study. This is very close to dependences from the ITER database for dischar

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:

Within the range of plasma shapes and plasma currents investigated, the electron confinement time, Tau_E increases with density, elongation and negative triangularity (-0.4

The aim of this paper is to present a signal processing algorithm that, applied to the raw Locked Mode signal, allows us to obtain a disruption indicator in principle exploitable on different tokamaks. A common definition of such an indicator for different ...

A steady-state, fully noninductive plasma current has been sustained for the first time in a tokamak using electron cyclotron current drive only. In this discharge, 123 kA of current have been sustained for the entire gyrotron pulse duration of 2 s. Careful distribution across the plasma miner radius of the power deposited from three 0.5-MW gyrotrons was essential for reaching steady-state conditions. With central current drive, up to 153 kA of current have been fully replaced transiently for 100 ms. The no

The TCV tokamak has 16 poloidal field coils for plasma shaping, distributed around the vacuum vessel. Experiments are described that determine the relative merits of different coil positions for controlling the unstable vertical movement of elongated plasmas. The results show over an order of magnitude variation in the amplitude of the plasma vertical position response to voltages applied to the different coils. The currents induced in the vessel, the required reactive feedback power and the ohmic power dis

Modulation of the amplitude of externally injected electron cyclotron (EC) power is a frequent method used to determine the radial power deposition profile in fusion plasmas. There are many tools to analyze the plasma response to the power modulations unde ...

Developments in the real time control hardware on Tokamak à Configuration Variable (TCV) coupled with the flexibility of plasma shaping and electron cyclotron (EC) heating and current drive actuators are opening many opportunities to perform real time expe ...

The Tokamak Configuration Variable (TCV) tokamak (R = 0.88 m, a < 0.25 m, B < 1.54 T) programme is based on flexible plasma shaping and heating for studies of confinement, transport, control and power exhaust. Recent advances in fully sustained off-axis electron cyclotron current drive (ECCD) scenarios have allowed the creation of plasmas with high bootstrap fraction, steady-state reversed central shear and an electron internal transport barrier. High elongation plasmas, kappa = 2.5, are produced at low nor

A new vertical position control system, including an internal active coil, has become operational on TCV. The new system has made it possible to stabilize plasmas with open loop growth rates up to 4400 s(-1), currents up to 1.0 MA and elongations up to 2.58. The closed loop stability of the new system has been analysed with a numerical model in which the plasma is assumed to be undeformable, and the power supply outputs are delayed with respect to their inputs. Model predictions agree with the main experime

The ITER high-frequency (HF) magnetic diagnostic system has to provide essential measurements of MHD instabilities with vertical bar delta B-MEAS/B-POL vertical bar similar to 10(-4) (similar to 1 G) for frequencies up to 2 MHz to resolve toroidal mode numbers (n) in the range vertical bar n vertical bar = 10 to vertical bar n vertical bar = 50. A review of the measurement requirements for HF MHD instabilities in ITER was initiated during the TW4 work-program and led to significant interest for physics and

An edge-localized mode (ELM) H-mode regime, supported by electron cyclotron heating, has been successfully established in a snowflake (second-order null) divertor configuration for the first time in the TCV tokamak. This regime exhibits 2 to 3 times lowe ...

The effect of ELMs on confinement in ohmic H-modes has been investigated by analysing the rates of change of global parameters such as the electron content and the stored energy as a function of ELM frequency. In double-null H-modes, ELMs are found to expel on average 2% of the electron content and 2.5% of the stored energy. In single-null discharges which are separated by more than 2.2 cm from the inner wall, larger ELMs are observed which expel on average 3-7% of the electron content and 3-12% of the stor

Jean-Marc Moret

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Assessment of the ITER High-Frequency Magnetic Diagnostic Set

Overview of the EUROfusion Tokamak Exploitation programme in support of ITER and DEMO

'Profile consistency' features in shaped sawtoothing ohmic TCV plasmas

Physics design of a saddle coil system for TCV

Recent Results from the Tcv Tokamak

Overview of alfven eigenmode experiments in jet

Real-time data transfer in the TCV advanced plasma control system

On the dependence of energy confinement on elongation in single null divertor plasmas

Control of electron internal transport barriers in TCV

Preliminary Confinement Studies during ECRH in TCV

A locked mode indicator for disruption prediction on JET and ASDEX upgrade

Steady-state fully noninductive current driven by electron cyclotron waves in a magnetically confined plasma

On locating the poloidal field coils for tokamak vertical position control

Multiple EC power deposition locations tracking by break-in-slope analysis in TCV plasmas

Real time control of plasmas and ECRH systems on TCV

An overview of results from the TCV tokamak

Feedback stabilization of axisymmetric modes in the TCV tokamak using active coils inside and outside the vacuum vessel

Assessment of the ITER high-frequency magnetic diagnostic set

"Snowflake" H Mode in a Tokamak Plasma

Effect on confinement of edge-localized modes in TCV