ABSTRACT
In this work, a non-intrusive, spatially resolved, spectro-tomographic optical diagnostic of the electronic density and temperature on the linear plasma column Mistral is presented. Coupling of spectroscopy and tomography technique gives access to the local plasma light emission at different wavelengths (visible and near IR) in an argon plasma. Taking advantage of the symmetry of the Mistral experiment, the diagnostic results are validated and the plasma is found to correspond to a corona equilibrium state. With the use of another spectrometer and a Langmuir probe, we propose a non-intrusive method to determine the electronic density and temperature of each pixel of the tomographic images of the plasma. The obtained results are in good agreement with the Langmuir probe ones.
ABSTRACT
In this paper, we describe a newly installed tomography diagnostic on the linear magnetized plasma device Mistral. The diagnostic is composed of 128 lines of sight covering a 20 cm diameter section and an acquisition rate up to 1 MHz. The measurements are done in the visible spectrum using silicon photomultiplier arrays that require a lower amplification voltage than photomultiplier tubes for similar gains and have a fast response. Tomographic reconstruction of a rotating plasma mode is shown to illustrate the capabilities of the diagnostic.
ABSTRACT
The present work concerns the development of a W sources assessment system in the framework of the tungsten-W environment in steady state tokamak project that aims at equipping the existing Tore Supra device with a tungsten divertor in order to test actively cooled tungsten Plasma Facing Components (PFCs) in view of preparing ITER operation. The goal is to assess W sources and D recycling with spectral, spatial, and temporal resolution adapted to the PFCs observed. The originality of the system is that all optical elements are installed in the vacuum vessel and compatible with steady state operation. Our system is optimized to measure radiance as low as 1016 Ph/(m2 s sr). A total of 240 optical fibers will be deployed to the detection systems such as the "Filterscope," developed by Oak Ridge National Laboratory (USA) and consisting of photomultiplier tubes and filters, or imaging spectrometers dedicated to Multiview analysis.
ABSTRACT
The turbulent regime of a rotating magnetized plasma column has been studied. The detection and the spatiotemporal analysis of structures by means of conditional sampling techniques is performed. Because of the overall rotation and centrifugal effects, the structures inside the turbulence move on average along a spiral trajectory leading to a net radial convection of the charged particles to the walls. The development of a poloidal electric field inside the structures has been measured. It leads to the observed outwards radial E x B drift in agreement with the expectations of recent theoretical works.
ABSTRACT
Hydrogen H(alpha) shift is measured in a plasma characterized by a noticeable coupling due to a high electron density (N(e)>/=2x10(18) cm(-3)) and a relatively low temperature (T=8900 K). The plasma is produced by a single laser breakdown in an underwater medium, creating a stable and radially homogeneous plasma. The results cannot be explained by the known contributions to the shift, which predict shifts by a factor of 2 greater than the experimental shifts. A contribution called dipole ionic-electronic shift (DIES) is introduced. The data presented in this work constitute the experimental discovery of this phenomenon. Indeed, the total theoretical shifts obtained taking into account the DIES are in excellent agreement with our experimental values.