A5078256856- Magnetic confinement fusion research
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Fusion materials and technologies
- Plasma Diagnostics and Applications
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Spacecraft and Cryogenic Technologies
- Nuclear Physics and Applications
- Electromagnetic Launch and Propulsion Technology
- Nuclear reactor physics and engineering
- Laser Design and Applications
- Transportation Systems and Safety
- Silicon and Solar Cell Technologies
- Geomagnetism and Paleomagnetism Studies
- Gyrotron and Vacuum Electronics Research
- Tribology and Lubrication Engineering
- Scientific Measurement and Uncertainty Evaluation
- Laser and Thermal Forming Techniques
- Magnetic Properties and Applications
- Vacuum and Plasma Arcs
- Astronomical Observations and Instrumentation
- Semiconductor Lasers and Optical Devices
- Electromagnetic Compatibility and Measurements
- Atomic and Molecular Physics
Forschungszentrum Jülich
1996-2009
Max Planck Society
2007
Royal Military Academy
1986-1993
École Normale Supérieure - PSL
1986-1989
Stadtwerke Jülich (Germany)
1981-1989
Laboratoire de Physique des Plasmas
1986
Belgian Nuclear Research Centre
1986
Stationary high energy confinement is observed on TEXTOR-94 for times limited only by the flux swing of transformer using strong edge radiation cooling. Necessary tools are feedback control radiated power and plasma content. At highest densities obtained (up to 1.2 Greenwald limit), exceeds edge-localized-mode-free H-mode scaling ITERH93-P more than 20%. β limits reached with fH89/qa≈0.6. No detrimental effect seeded impurity seen. These discharges meet many conditions necessary a fusion...
The first results of the Dynamic Ergodic Divertor in TEXTOR, when operating m/n=3/1 mode configuration, are presented. deeply penetrating external magnetic field perturbation this configuration increases toroidal plasma rotation. Staying below excitation threshold for m/n=2/1 tearing mode, rotation is always direction current, even if projection rotating opposite direction. observed consistent with a radial electric field, generated by an enhanced electron transport ergodic layers near...
The radiative improved (RI) mode is a tokamak regime offering many attractive reactor features. In the article, RI of TEXTOR-94 shown to follow same scaling as linear ohmic confinement and thus identified one most fundamental operational regimes. current understanding derived from experiments modelling conditions necessary for sustaining reviewed, are mechanisms leading L-RI transition. article discusses compatibility high impurity seeding with low central power density burning reactor, well...
Improved confinement is achieved on TEXTOR under high power conditions (up to 4 MW of additional heating with NBI-co+ICRH, NBI-co+counter or NBI-co+counter+ICRH) edge radiative cooling employing silicon neon as the radiating impurities. It shown that in quasi-stationary up 85% input can be radiated. Such fractions offer possibility utilizing these techniques facilitate exhaust problem for a Tokamak reactor. Discharges exhibit enhanced properties at densities, e.g. central line averaged...
TEXTOR is the Tokamak Experiment for Technology Oriented Research in field of plasma-wall interaction. The scope includes a detailed analysis particle and energy exchange between plasma surrounding chamber as well active measures to optimize first wall boundary region. medium-sized tokamak belonging class moderate-field but large-volume devices having circular cross section an iron core. major radius 1.75 m, minor 0.47 m. maximum current 0.8 MA, 3 T, pulse length 10 s. fed directly from...
An overview of the results obtained so far for radiative I-mode regime on upgraded Torus Experiment Technology Oriented Research (TEXTOR-94) [Proceedings 16th IEEE Symposium Fusion Engineering (Institute Electrical and Electronics Engineers, Piscataway, NJ, 1995), Vol. 1, p. 470] is given. This under quasistationary conditions with edge neon seeding in a pumped limiter tokamak circular cross section. It combines high confinement β (up to normalized beta, βn=2) low q values (down qa=2.8)...
An overview is presented of recent experiments with radiating mantles on limiter and divertor machines, realizing simultaneously high confinement density at high-radiation levels. A variety operational regimes has been observed the characteristics each are documented. High-performance plasmas (i.e. edge localized mode (ELM)-free H-mode quality normalized beta values simultaneously) have demonstrated under quasistationary conditions during maximum flattop time machine (equal to tens times)...
The paper summarizes the main results obtained during first six months of experimental work on TEXTOR with ohmically heated plasmas. machine(R = 175 cm; a 45-50 cm) was operated at wall temperatures up to 303 oC hydrogen gas, toroidal field 2 T and maximum plasma current 500 kA, yielding central electron 1.2 keV, line-averaged densities 4 x 1013 cm-3 discharge durations 2.7 sec (for Ip⩽340 kA). Besides providing long-lasting reproducible plasmas for forthcoming interaction research,...
Four new low field side antennae grouped in pairs have been installed on TEXTOR. It is found that the interaction with wall (density rise, impurity generation) significantly reduced when operating each pair out of phase ( pi ) as opposed to (0). The beneficial effect configuration obtained without drop plasma loading. This experimental property shown, from theory, be explained by judicious choice geometrical configuration. A further improvement made possible an appropriate conditioning (wall...
Recently, the dynamic ergodic divertor (DED) of TEXTOR has been studied in an m/n = 3/1 set-up which is characterized by a relatively deep penetration perturbation field. The field creates (a) helical divertor, (b) pattern and/or (c) excitation tearing modes, depending on whether DED current static, rotating co-current direction or counter-current direction. Characteristic properties such as high recycling regime enhanced shielding have studied. A strong effect ergodization spin up plasma...
Ion cyclotron heating on TEXTOR has now reached the Megajoule level. The scenario is normally mode conversion but occasionally minority in a D-(H) plasma. With appropriate wall conditioning by carbonization more than 1 MW of RF power been injected for long pulse durations ( approximately s). ICRF heated plasma characterized quasi-stationarity all parameters, little if no impurity increase and loop voltage reduction resulting total coupled to reaching six times remaining ohmic input. Evidence...
AbstractA multimegajoule ion cyclotron resonance heating (ICRH) experiment was installed on the Torus Experiment for Technology-Oriented Research (TEXTOR) tokamak. The system consists of two independent power lines each designed to generate and launch 1.5 MW radio-frequency (rf) into machine during a 3-s period in 25- 29-MHz frequency range. Each line following items: (a) 1.5-MW transmitter, (b) transmission system, including two-stub tuner, made pressurized 155.6-mm (6.125-in.) 228.6-mm...
The plasma-facing surfaces of TEXTOR have recently been coated (plasma chemical deposition) by a thin layer hydrogen-rich carbon and boron (ratio 1:1). paper describes the improved plasma performance which resulted when this coating replaced amorphous (a-C:H) used before. main differences were pronounced reduction radiation losses, decrease Zeff from 1.4 to 1.2 significant change in hydrogen recycling: recycling coefficient was smaller than unity during current flat top at wall temperature...
The TEXTOR research programme focuses on the systematic analysis of plasma wall interaction, development a suitable system and production quasi-stationary long-pulse high-temperature plasmas with tolerable impurity concentrations, well-defined boundary layer relevant particle power fluxes through boundary. authors describe method carbonization developed in Julich some characteristic features obtained this for both metal limiters graphite limiters. Moreover, effect ICRH heating (2 MW, 1 sec)...
A new regime of enhanced confinement (I-mode) is found in plasmas with circular cross-sections the pump limiter tokamak TEXTOR boronized walls. This obtained three types auxiliary heating, namely NBI co-injection, counter-injection+ICRH and co-injection+NBI counter-injection, has many similarities H-mode divertor tokamaks. The energy times these discharges scale as favourably those stationary edge localized modes. detailed analysis scaling time plasma current, heating power density...
Neutral beam injection (NBI-co and NBI-counter), ICRH their combinations have been compared on TEXTOR for what concerns the heating effect energy anisotropy confinement. In most of cases, stationary heated plasma conditions obtained with boronized wall. The main results are: (i) Production a hot ion mode NBI-co. It is characterized by large anisotropy, noninductively driven toroidal current stabilization sawteeth (of monster type) due to tail. (ii) Significant enhancement these effects when...
Co-injection (Do to D+) applied TEXTOR leads a hot ion mode regime with enhanced confinement. A synergistic increase of the beam effects is observed addition ICRH at omega =2 cD= cH (H minority heating scenario) resulting, beside other reviewed effects, in significant temperature and driven current (respectively larger than 30% 50% for an RF power comparable NBI one). The large efficiency also remains when added balanced injection up maximum achieved beta (=2/3 Troyson limit more 6 MW...
The Wendelstein 7-X stellarator is presently under construction and assembly in Greifswald, Germany. Its ultimate goal to verify that such magnetic confinement concept a viable option for demonstration fusion power-plant. superconducting magnet system, capable generate average field up 3 Tesla at the axis, basically composed of non-planar planar coils, central support structure which they are connected. This system complex mechanical has fulfil demanding requirements terms accuracy field,...
The stellarator Wendelstein 7-X is presently under construction and assembly in Greifswald, Germany. One of the main structural elements which have to take electromagnetic forces superconducting coil system are narrow support (NSE). They placed between non planar coils very high compressive while relative sliding tilting must be allowed. design has been optimised with regard a proper load distribution among all taking also into account manufacturing tolerances. paper describes design,...