A5017141171- Gyrotron and Vacuum Electronics Research
- Particle accelerators and beam dynamics
- Microwave Engineering and Waveguides
- Magnetic confinement fusion research
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Pulsed Power Technology Applications
- Plasma Diagnostics and Applications
- Acoustic Wave Resonator Technologies
- Microwave-Assisted Synthesis and Applications
- Superconducting and THz Device Technology
- Electromagnetic Simulation and Numerical Methods
- Photonic and Optical Devices
- Fusion materials and technologies
- Microwave and Dielectric Measurement Techniques
- Ionosphere and magnetosphere dynamics
- Terahertz technology and applications
- Physics and Engineering Research Articles
- Induction Heating and Inverter Technology
- Dust and Plasma Wave Phenomena
- Metamaterials and Metasurfaces Applications
- Advanced Antenna and Metasurface Technologies
- Electromagnetic Compatibility and Measurements
- Muon and positron interactions and applications
- Semiconductor Lasers and Optical Devices
Karlsruhe Institute of Technology
2015-2024
National Agency for New Technologies, Energy and Sustainable Economic Development
2022
University of Padua
2022
Thales (France)
2017-2019
École Polytechnique Fédérale de Lausanne
2017-2019
Fusion for Energy
2016-2019
Institute of Applied Physics
2017
Institute of Highway Engineers
2016-2017
Budker Institute of Nuclear Physics
2012-2017
Siberian Branch of the Russian Academy of Sciences
2017
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...
This review discusses the present state-of-the-art of passive high-power microwave components for applications in systems RF plasma generation and heating, diagnostics, materials processing, spectroscopy, communication, radar ranging imaging, drivers next high-field-gradient electron-positron linear colliders. The paper reports on overmoded transmission such as smooth-wall waveguides, HE/sub 11/ hybrid mode waveguides quasi-optical TEM/sub 00/ beam waveguides. These include various types...
The Wendelstein 7X (W7-X) stellarator (R = 5.5 m, a 0.55 B < 3.0 T), which at present is being built Max-Planck-Institut für Plasmaphysik, Greifswald, aims demonstrating the inherent steady-state capability of stellarators reactor-relevant plasma parameters. A 10-MW electron cyclotron resonance heating (ECRH) plant with continuous-wave (cw) under construction to meet scientific objectives. physics background different and current drive scenarios presented. expected parameters are calculated...
A 2-MW continuous-wave (CW) 170-GHz coaxial-cavity gyrotron for electron cyclotron heating and current drive in the International Thermonuclear Experimental Reactor (ITER) is under development within European Gyrotron Consortium (EGYC1), a cooperation between research institutions. To support of industrial prototype CW gyrotron, short-pulse tube (preprototype) used at KIT Karlsruhe (former FZK) experimental verification design critical components, like gun, beam tunnel, cavity, quasi-optical...
The CERN Resonant WISP Search (CROWS) probes the existence of Weakly Interacting Sub-eV Particles (WISPs) like axions or hidden sector photons. It is based on principle an optical light shining through wall experiment, adapted to microwaves. Critical aspects experiment are electromagnetic shielding, design and operation low loss cavity resonators detection weak sinusoidal microwave signals. Lower bounds were set coupling constant $g = 4.5 \cdot 10^{-8} $GeV$^{-1}$ for axion particles with a...
Progress in the worldwide development of high-power gyrotrons for magnetic confinement fusion plasma applications is presented. Gyrotron oscillators are used electron cyclotron heating, current drive, stability control, and diagnostics. After technology breakthroughs research on gyrotron components 1990s, significant progress has been achieved 2000s, field long-pulse continuous wave (CW) operation a wide range frequencies. Currently, 1-MW-class CW tokamak ITER (170 GHz), stellarator...
The European DEMO is a pulsed device with pulse length of 2 hours. functions devoted to the heating and current drive system are: plasma breakdown, ramp-up flat-top where fusion reactions occur, control during phase, finally ramp-down. EU-DEMO project was in Pre-Concept Design Phase 2014-2020, meaning that some cases, design values precise requirements from physics point view were not yet frozen. A total 130 MW considered for all phases plasma: flat top, 30 required neoclassical tearing...
Abstract This work reports on measurements and calculations (coupled mode equations) the conversion of circular electric TE0n gyrotron compositions (TE01 to TE04) at 28 70 GHz linearly polarized TE11 by means converter systems using periodic waveguide wall perturbations. Mode transducers with axisymmetric radius perturbations transform mixture more convenient TE01 for long-distance transmission through overmoded waveguides. Proper matching phase differences between modes lengths perturbation...
The feasibility of manufacturing a 2-MW CW coaxial cavity gyrotron at 170 GHz has been demonstrated and data required for fabrication an industrial tube have obtained. An engineering design prototype started recently with the goal to provide gyrotrons microwave output power International Thermonuclear Experimental Reactor (ITER). critical components as electron gun, RF system will be verified under realistic conditions short pulses using experimental Forschungszentrum Karlsruhe.
The first plasma experiments on the W7AS advanced stellarator were conducted in October 1988, after magnetic surface mapping. characteristics of device are described. During phase operation, 70 GHz ECF was used to generate and heat a 'currentless' which maintained quasi-steady state for typically 0.5 s. Effects configuration confinement measures deal with observed current (bootstrap ECF-driven current) investigated. Preliminary results transport analysis presented compared predictions models.
The next step in the Wendelstein stellarator line is large superconducting device 7-X, currently under construction Greifswald, Germany. Steady-state operation an intrinsic feature of stellarators, and one key element 7-X mission to demonstrate steady-state plasma conditions relevant for a fusion power plant. device, on hand, requires implementation special technologies, giving rise technical challenges during design, fabrication assembly such device. On other also physics development at...
A spatially extended planar 75 GHz free-electron maser with a hybrid two-mirror resonator consisting of two-dimensional upstream and traditional one-dimensional downstream Bragg reflectors driven by two parallel-sheet electron beams 0.8 MeV/1 kA has been elaborated. For the highly oversized interaction space (cross section 45×2.5 vacuum wavelengths), distributed feedback allowed realization stable narrow-band generation that includes synchronization emission from both beams. As result,...
The development of high-power gyrotrons (118 GHz, 140 GHz) in continuous-wave (CW) operation for heating nuclear fusion plasmas has been progress several years a joint collaboration between different European research institutes and industrial partners. 140-GHz gyrotron being under the installation at W7-X stellarator now construction IPP Greifswald, Germany, operates TE/sub 28,8/ mode is equipped with diode type magnetron injection electron gun, an improved beam tunnel, high mode-purity...
A Bragg reflector composed of periodic cylindrically symmetric corrugations can provide a reflection nearly unity through the principles constructive interference, allowing formation frequency selective resonator. Mode conversion will occur, but be reduced by tapering amplitude corrugations. Reflection measurements are compared with theoretical predictions for untapered sinusoidal and rectangular corrugation as well tapered according to Hamming-window prescription. Measurements resonators...
The first series tube of the gyrotrons for 10-MW electron cyclotron resonance heating system stellarator W7-X was tested at Forschungszentrum Karlsruhe (FZK) and yielded a total output power 0.98 MW, with an efficiency 31% (without single-stage depressed collector) in short-pulse operation 0.92 MW pulses 180 s (efficiency almost 45% depression voltage 29 kV). Gaussian mode 0.91 MW. pulselength full (1 MW) is limited FZK by available supply. At reduced beam current, it possible to operate...
Megawatt gyrotrons are found to suffer from various parasitic oscillations, in particular, RF oscillations the beam tunnel prior desired interaction zone (the cavity). This paper describes experimental results a gyrotron experiment which was dedicated investigate and verify improved beam-tunnel structures. A system for spectral measurements new analysis method presented. The theoretical predictions on effect validate corresponding structure. In addition, other types of were observed explained.