Publications de René Chavan | EPFL Graph Search

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The purpose of the ITER electron cyclotron resonance heating (ECRH) upper launcher (UL), or antennae will be to provide localised current drive by accurately directing mm-wave beams up to 2MW, out of the four allocated upper port plugs, at chosen rational ...

The ITER high-frequency (HF) magnetic diagnostic system has to provide essential measurements of MHD instabilities with |deltaBMEAS/BPOL|~10^-4 (~1G) for frequencies up to 2MHz to resolve toroidal mode numbers (n) in the range |n|=10-50. 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 real-time control issues in measuring modes with |deltaBMEAS| as low as ~10^-4G at the position of the sensors

Four Electron Cyclotron Heating Upper Launchers (ECHUL) will be used at ITER to counteract magneto-hydrodynamic plasma instabilities by targeting them with up to 20 MW of mm-wave power at 170 GHz. The millimeter waves are guided through a set of fixed mirr ...

Fully noninductive, steady-state electron cyclotron current drive (ECCD) has been demonstrated for the first time in experiments carried out in the tokamak a configuration variable (TCV) [O. Sauter , Phys. Rev. Lett. 84, 3322 (2000)]. By appropriately distributing six 0.45 MW ECCD sources over the discharge cross section, fully noninductive, stable, and stationary plasmas with I-p up to 210 kA were obtained for the full discharge duration of 1.9 s, corresponding to more than 900 energy confinement times and

Four electron cyclotron heating upper launchers (ECHULs) will be used at ITER to counteract magnetohydrodynamic plasma instabilities by targeting them with up to 24 MW of mm-wave power at 170 GHz. This mm-wave power is injected through eight ex-vessel (EV) ...

This poster is an overview of work carried out on the design of the ITER high-frequency magnetic diagnostic coil (HF sensor). In the first part, the ITER requirements for the HF sensor are presented. In the second part, the ITER reference design of the HF sensor has been assessed and showed some potential weaknesses, which led us to the conclusion that alternative designs could usefully be examined. Several options have been explored, and are presented in the third part: (3.1) direct laser cutting a metalli

The ITER Heating and Current Drive Upper Launcher (H&CD EC UL) uses a pneumomechanical steering-mirror assembly (SMA) to steer the RF beams for their deposition in the appropriate location in the plasma to control magnetohydrodynamic activity (neoclassical ...

The main objective of the ITER ECRH upper launcher (UL) is to control magnetohydrodynamic activity, in particular neoclassical tearing modes (NTMs), by driving several MW of EC Current near the q = 1, 3/2, 2 flux surfaces, where NTMs are expected to occur. ...

The current status of the ITER magnetics diagnostic is summarised. The various risks are discussed on the basis of when they could be present during ITER operation and appropriate mitigation is reviewed. An implementation risk or common mode operation fail ...

The mirror M3 is a part of the in-vessel quasi-optical beam propagation system for the ITER electron cyclotron heating upper launcher (ECHUL). The millimeter waves are guided through fixed mirror sets (M1, M2, and M3) and the front steering mirror set (M4) ...

A 'standard', single null lower diverted discharge has been developed to enable continuous monitoring of the first wall conditions and to characterise the effectiveness and influence of wall conditioning in the TCV tokamak. Measurements over a period encompassing nearly 2000 ohmic discharges of varying configuration and input power show the global confinement time and main plasma impurity concentrations to be good general indicators of the first wall condition, whilst divertor target profiles demonstrate st

The TCV tokamak contributes to the physics understanding of fusion plasmas, broadening the parameter range of reactor relevant regimes, by investigations based on an extensive use of the existing main experimental tools: flexible shaping and high power rea ...

The ITER ECRH upper launcher (UL) uses a steering mechanism assembly (SMA) to steer the beams in the appropriate location for controlling magnetohydrodynamic (MILD) activity in the plasma (NTMs and sawtooth oscillations). ...

Four of the 16 ITER upper port plugs will be devoted to electron cyclotron resonance heating (ECRH) in order to control the magneto-hydrodynamic (MHD) instabilities. ...

The Double Closure Plate Sub-Plate (DCPSP) was introduced in the Electron Cyclotron Upper Launcher (EC UL) design in order to minimize the openings exposing the interior of the Port Plug (PP) to the port cell; avoiding thus the near environment activation ...

A detailed description of the Langmuir probe electronics upgrade for TCV (Tokamak a Configuration Variable) is presented. The number of amplifiers and corresponding electronics has been increased from 48 to 120 in order to simultaneously connect all of the ...

Six Electron Cyclotron (EC) launchers are currently envisaged to be installed at the Equatorial Ports (EP) of the EU DEMO Tokamak with the purpose of delivering up to 130 MW for plasma bulk heating (BH), thermal instability (TI) control and magnetohydrodyn ...

Four of the 16 ITER upper port plugs will be devoted to electron cyclotron resonance heating (ECRH) in order to control magnetohydrodynamic (MHD) instabilities [1,2]. In order to achieve the stabilisation of the neoclassical tearing modes (NTM) and sawtooth oscillation, a deposition of a very localized and peaked current density profile over a broad poloidal steering range is required.

For the EU DEMO Tokamak, Electron Cyclotron (EC) launching systems for plasma heating and stabilization are under development. Various concepts for the optical system are currently studied of which the Mid Steering Antenna (MSA) with a steering mirror at a ...

René Chavan

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Design status of the ITER ECRH upper launcher mm-wave system

Analysis of the ITER High-Frequency Magnetic Diagnostic Set

Design optimization of the Upper Steering Mirror Assembly (USMA) for ITER ECHUL in view of disruptive events

Steady-state fully noninductive operation with electron cyclotron current drive and current profile control in the tokamak a configuration variable (TCV)

Design and Numerical Analyses of the M4 Steering Mirrors for the ITER Electron Cyclotron Heating Upper Launcher

Design of the ITER High-Frequency Magnetic Diagnostic Coils

Progress on the design of various magnetic sensors for ITER: diamagnetic and flux loops, high frequency coils, in-vessel and divertor coils, ex-vessel coils, and external Rogowskis

Progress on the ITER H&D EC Upper Launcher Steering-Mirror Control System

Progress on the ITER ECRH upper launcher steering mirror identification and control

The magnetics diagnostic set for ITER

Design Concept and Thermal & x2013;Mechanical Analysis of the Optical Mirror (M3) for the ITER ECH Upper Launcher

Divertor target profiles and recycling studies in TCV single null lower standard discharges

A scoping study of the application of neutral beam heating on the TCV tokamak

Progress on the ITER Electron Cyclotron Heating and Current Drive Upper Launcher Steering Mirror Control System

Progress on the design and manufacturing of the mirrors for the ITER Electron Cyclotron Heating and Current Drive upper launcher

Seismic analyses of the Double Closure Plate Sub-Plate for the ITER Electron Cyclotron Upper Launcher during the Vacuum Vessel baking scenario

Langmuir probe electronics upgrade on the tokamak a configuration variable

Design description and thermo-hydraulic assessment of the steering mirror for the EU DEMO Electron Cyclotron system

Design and manufacturing of the ITER ECRH Upper Launcher mirrors

Structural pre-conceptual design studies for an EU DEMO equatorial EC port plug and its port integration