Speaker
Natalia Krawczyk
(Department of Nuclear Fusion and Plasma Spectroscopy)
Description
The Wendelstein 7-X (W7-X) stellarator started its operation at the end of 2015. The first operation phase is conducted both with helium and hydrogen as working gas and has achieved first plasmas in the order of 500ms at the time this abstract has been written. The initial experiments have also been devoted to commissioning, tests and optimization of diagnostic systems.
In this paper we report on the commissioning of the Pulse Height Analysis (PHA) diagnostic. The PHA measures radiation from the plasma core in the energy range of 0.25 - 20 keV in order to estimate the electron temperature and core plasma impurity content. The PHA design is optimized for measurements in high performance plasmas in future operation phases of Wendelstein 7-X. The commissioning phase allowed to test functionalities and to validate the operation of the PHA. By applying the appropriate filters, each of the 3 channels observe the radiation spectrum in selected energy ranges. The plasma radiation is recorded by Silicon Drift Detectors, which have been specifically adapted to PHA with regard to their energy resolution better than 180eV. The temporal resolution of the PHA system is about 100 ms.
The paper presents commissioning of the PHA system conducted in the first experimental campaign of W7-X. Findings are suffering at this stage from low densities and temperatures (with regard to counting rates) but the commissioning and characterization both in helium and hydrogen plasmas has been obtained and will be presented. Spectra from W7-X He- and H-plasmas will be also compare to simulation results obtained with the ray-X code.
Co-authors
Agata Czarnecka
(Department of Nuclear Fusion and Plasma Spectroscopy, Institute of Plasma Physic and Laser Microfusion, Warsaw, Poland)
Christoph Biedermann
(Max-Planck-Institut für Plasmaphysik, , Wendelsteinstrasse 1, 17491 Greifswald, Germany)
Henning Thomsen
(Max-Planck-Institut für Plasmaphysik, , Wendelsteinstrasse 1, 17491 Greifswald, Germany)
Jacek Kaczmarczyk
(Department of Nuclear Fusion and Plasma Spectroscopy, Institute of Plasma Physic and Laser Microfusion, Warsaw, Poland)
Monika Kubkowska
(Department of Nuclear Fusion and Plasma Spectroscopy, Institute of Plasma Physic and Laser Microfusion, Warsaw, Poland)
Natalia Krawczyk
(Department of Nuclear Fusion and Plasma Spectroscopy, Institute of Plasma Physic and Laser Microfusion, Warsaw, Poland)
Slawomir Jablonski
(Department of Nuclear Fusion and Plasma Spectroscopy, Institute of Plasma Physic and Laser Microfusion, Warsaw, Poland)
Tomasz Fornal
(Department of Nuclear Fusion and Plasma Spectroscopy, Institute of Plasma Physic and Laser Microfusion, Warsaw, Poland)
