A5029642850- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Fusion materials and technologies
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Ionosphere and magnetosphere dynamics
- Nuclear reactor physics and engineering
- Atomic and Subatomic Physics Research
- Diamond and Carbon-based Materials Research
- Nuclear Materials and Properties
- Physics of Superconductivity and Magnetism
- Laser-induced spectroscopy and plasma
- Risk and Safety Analysis
- Semiconductor materials and devices
- Atomic and Molecular Physics
- Scientific Measurement and Uncertainty Evaluation
Ghent University
2004-2008
Forschungszentrum Jülich
2004
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...
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...
The concept of the dynamic ergodic divertor (DED) is based on plasma edge ergodization by a resonant perturbation. Such closely related to helical or island divertors in stellerators. base mode DED perturbation field can be m/n = 12/4, 6/2 3/1. 3/1 with its deep penetration provides excitation tearing modes. This topic was presented elsewhere. In this contribution we concentrate properties DED. We report characterization topology, transport fields, impurity and density limit behaviour.The...
The Dynamic Ergodic Divertor (DED) has recently been taken into operation on TEXTOR. device is rather flexible and allows the investigation of very different questions. In present context we concentrate divertor aspect results m/n=12/4 base mode. DED-field generates proper ergodic zone an area open magnetic field lines, laminar tangle structure. properties resemble region a poloidal divertor. However, distribution density temperature highly 3D strongly related to structure zones. structures...
We have developed tunnel probes for localized measurements of the electron and ion temperature in edge plasma region smaller tokamaks stellarators. A normal probe Te consists a metallic 5 mm diameter length, with axis parallel to magnetic field. One side is open, other closed by backplate, isolated from tunnel. If both electrodes are biased negatively, ions flow into office, their current distributed between backplate. The ratio two currents function Te. With an additional diaphragm front...
Abstract Localised ion temperature measurements can only be performed with special electric probes where the electron component of current is kept off from collector. In a strong magnetic field effect utilised that gyro‐radius much smaller than ions. This method was developed by Katsumata and Okazaki (Japan J. Appl. Phys. 6 , 123 (1967)). We have used so‐called tunnel probe (which consists conductive tunnel, terminated an isolated back plate) adding diaphragm in front. Thereby prevented...
The tunnel probe is a new kind of Langmuir for fast dc measurements ion flux and electron temperature in the tokamak scrape-off layer. calibrated using two-dimensional kinetic analysis current distribution on concave conductors. Though qualitative agreement with classical was found, given by several times lower. One possible explanation might be an overestimation probe, due to non-Maxwellian velocity which can modelled first approach as two-temperature distribution. Hence influence small...
Abstract The possible influence of a small population suprathermal electrons on the tunnel probe, new kind Langmuir probe for fast DC measurements ion flux and electron temperature in tokamak scrape‐off layer, has been investigated by numerical simulations. It was found that can current distribution over inner plasma collecting surfaces thus T e measurements. depends structure Debye magnetic sheath inside probe. Therefore, we make here first attempt at investigating scaling those sheaths. (©...
An analytical model previously developed to study the structure of magnetic field for TEXTOR-DED [S.S. Abdullaev et al. Phys. Plasmas, 6, 153 (1999)] is applied similar Ergodic Divertor Tore Supra tokamak [Ph. Ghendrih, Plasma Control. Fusion, 38, 1653 (1996)]. The coil configuration ED consists six modules equidistantly located along toroidal direction on low-field-side torus with given and poloidal extensions. Hamiltonian formulation line equations in straight-field-line coordinates...