Spatially resolved determination of the electronic density and temperature by a visible spectro-tomography diagnostic in a linear magnetized plasma.

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.

A tomography diagnostic in the visible spectrum to investigate turbulence and coherent modes in the linear plasma column Mistral.

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.

Development of visible spectroscopy diagnostics for W sources assessment in WEST.

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.

Wall current probe: a non-invasive in situ plasma diagnostic for space and time resolved current density distribution measurement.

In the context of low temperature plasma research, we propose a wall current probe to determine the local charged particle fluxes flowing to the chamber walls. This non-intrusive planar probe consists of an array of electrode elements which can be individually biased and for which the current can be measured separately. We detail the probe properties and present the ability of the diagnostic to be used as a space and time resolved measurement of the ion and electron current density at the chamber walls. This diagnostic will be relevant to study the electron transport in magnetized low-pressure plasmas.