A5036946061- Gyrotron and Vacuum Electronics Research
- Particle accelerators and beam dynamics
- Magnetic confinement fusion research
- Superconducting Materials and Applications
- Microwave Engineering and Waveguides
- Plasma Diagnostics and Applications
- Fusion materials and technologies
- Acoustic Wave Resonator Technologies
- Particle Accelerators and Free-Electron Lasers
- Nuclear reactor physics and engineering
- Pulsed Power Technology Applications
- Photonic and Optical Devices
- Advanced Fiber Laser Technologies
- Ophthalmology and Visual Impairment Studies
- Glaucoma and retinal disorders
- Electrostatic Discharge in Electronics
- Aeolian processes and effects
- Silicon Carbide Semiconductor Technologies
- Graphite, nuclear technology, radiation studies
- Nuclear Physics and Applications
- Superconducting and THz Device Technology
- Tree Root and Stability Studies
- Fault Detection and Control Systems
- Soil erosion and sediment transport
- Optical Coatings and Gratings
École Polytechnique Fédérale de Lausanne
2013-2022
Swiss Paraplegic Center
2021
Karlsruhe Institute of Technology
2003-2017
École Normale Supérieure - PSL
2013
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2012
III V Lab
2012
CEA LETI
2012
Laboratoire de Physique des Plasmas
2006
California Institute of Technology
1986
University of California, Los Angeles
1981
In many tokamak and stellarator experiments around the globe that are investigating energy production via controlled thermonuclear fusion, electron cyclotron heating current drive (ECH&CD) used for plasma start-up, heating, non-inductive MHD stability control.ECH will be first auxiliary method on ITER.Megawatt-class, continuous wave (CW) gyrotrons employed as high-power millimeter (mm)-wave sources.The present review reports worldwide state-of-the-art of gyrotrons.Their successful...
Operating ITER in the reference inductive scenario at design values of Ip = 15 MA and QDT 10 requires achievement good H-mode confinement that relies on presence an edge transport barrier whose pedestal pressure height is key to plasma performance. Strong gradients occur such conditions can drive magnetohydrodynamic instabilities resulting localized modes (ELMs), which produce a rapid energy loss from region facing components (PFC). Without appropriate control, heat loads PFCs during ELMs...
DEMO (DEMOnstration Fusion Power Plant) is a proposed nuclear fusion power plant that intended to follow the ITER experimental reactor. The main goal of will be demonstrate possibility produce electric energy from reaction. injection high neutral beams one tools heat plasma up conditions. A conceptual design Neutral Beam Injector (NBI) for reactor, currently being developed by Consorzio RFX in collaboration with other European research institutes. High efficiency and low recirculating power,...
The plasma design point during stationary phase operation of EU-DEMO has been described extensively in the past, and assumptions employed for its definition have supported by various investigations. However, a snapshot is far not sufficient to ensure actual operability scenario. On contrary, both normal off-normal transients strong impact on machine design, providing most challenging requirements actuators. This be accounted from early phases on. In this paper, main originating operation,...
The European 1-MW, 170-GHz continuous wave industrial prototype gyrotron for electron cyclotron resonance heating and current drive on international thermonuclear experimental reactor was during 2016 under test at the Karlsruhe Institute of Technology (KIT) facility. In order to optimize operation, tube first thoroughly tested in short-pulse regime, with pulses that did not exceed 10 ms, a wide range operational parameters. Then, after proper conditioning tube, operation extended longer...
Experiments on a 100 GHz quasioptical (QO) gyrotron operating at the fundamental (ω=Ωce) are described. Powers larger than 90 kW an efficiency of about 12% were achieved. Depending electron beam parameters, frequency spectrum output can be either single moded or multimoded. One main advantages QO over conventional is its continuous tunability. Various techniques to tune have been tested, such as changing mirror separation, voltage, magnetic field. Within limitations present setup, 5%...
The European Gyrotron Consortium (EGYC) is responsible for developing one set of 170 GHz mm-wave sources, in support Europe's contribution to ITER. original plan targeting a 2 MW coaxial gyrotron currently under discussion, view essential delays and damages. This paper reports on the latest results plans with regard two prototypes, industrial prototype at CRPP's CW test stand modular pre-prototype KIT. was delivered CRPP end September 2011 reached an output power efficiency 45 % good RF beam...
Electron beam instabilities occurring in a gyrotron electron can induce an energy spread which might significantly deteriorate the efficiency. Three types of are considered to explain important discrepancy found between theoretical and experimental efficiency case quasi-optical gyrotrons (QOG): cyclotron maser instability (ECMI), electrostatic Bernstein (BI) Langmuir (LI). When magnetic field gradient drift tubes QOG is low, ECMI develop tube at very low currents. Experimental measurements...
High-frequency gyrotrons with high output power are mainly used for microwave heating and current drive in plasmas thermonuclear fusion. The development of high-power continuous wave (CW) operation has been progress several years a joint collaboration between different European research centers an industrial partner. status the 140-GHz continuously operating 1 MW stellarator Wendelstein 7-X will be described. An 890 kW achieved pulse length 3 min. limited by available high-voltage supply at...
The upgrade of the EC-system TCV tokamak has entered in its realization phase and is part a broader TCV. MW-class dual-frequency gyrotrons (84 or 126GHz/2s/1MW) are presently being manufactured by Thales Electron Devices with first gyrotron foreseen to be delivered at SPC end 2017. In parallel development, for extending level operational flexibility integration adds significant complexity evacuated 63.5mm-diameter HE11 transmission line system connected various low-field side top launchers....
The operation of a gyrotron based upon quasi-optical cavity is reported. mirrors were separated by 81 cm, allowing the use large enough in diameter to be principle compatible with CW operation. pulse length this experiment was 12 microseconds. operated between 113 GHz and 122 GHz, maximum output power 50 kW. highest efficiency observed 7·3%. powers efficiencies lower than originally anticipated, but when losses actual performance electron gun included, agreed well theoretical predictions on...
The pre-conceptual design for a European pulsed fusion reactor (DEMO1) is ongoing and one of the most challenging activities within scenario modeling studies deals with numerical investigations DEMO1 transient phases. This paper presents an investigation on both ramp-up ramp-down phases by selected plasma trajectories. Plasma evolution has clear impact engineering reactor, e.g. auxiliary power systems, current ramp-rates requirements coil system. Studies have been carried out fast tokamak...
A new model for simulating gyrotron oscillators in the monomode time-dependent linear self-consistent regime is presented. Starting from a nonlinear model, linearization and following simplification of based on moment approach, are described. This simplified represents numerically efficient allows to have deeper physical insight, particular, regimes dominated by effects such as gyro-backward wave instability. One specific case cavity studied detail compared with experimental results, special...
The operation of a 92 GHz quasi-optical gyrotron having resonator formed by spherical mirror and diffraction grating placed in −1 order Littrow mount is presented. A power 150 kW with Gaussian output pattern was measured. content the 98% less than 1% depolarization. By optimizing magnetic field at fixed frequency, maximum efficiency 15% reached.
A quasi-optical gyrotron (QOG) designed for operation at the fundamental ( fce≂100 GHz) exhibits simultaneous emission fce and 2fce (second harmonic). For a beam current of 4 A, 20% total rf power is emitted second harmonic. The experimental measurements show that excitation harmonic only possible when present. frequency locked by fundamental. Experimental evidence shows not excited, efficiency enhanced.