1,312 research outputs found
Influence of the magnetic filter field topology on the beam divergence at the ELISE test facility
No full textSpectroscopic diagnostics of glow discharge plasmas with non-Maxwellian electron energy distributions
No full textSpectroscopic diagnostics of glow discharge plasmas with non-Maxwellian electron energy distributions / K. Behringer ; U. Fantz. - In: Journal of physics. D. 27. 1994. S. 2128-213
Beam characterization by means of emission spectroscopy in the ELISE test facility
No full textThe ELISE (extraction from a large ion source experiment) test facility at IPP Garching hosts a RF H−/D− ion source and an acceleration system. Its target is to demonstrate the performance
foreseen for the ITER neutral beam injector (NBI) system in terms of extracted current density (H/D), fraction of co-extracted electrons and pulse duration. The size of the ELISE extraction
area is half that foreseen for the ITER NBI. This paper presents a detailed study of the ELISE beam divergence and uniformity. In particular, it was possible to describe the beam as the sum of
two components at very different divergence: about 2° versus 5° ÷ 7°. As test cases, the beam properties have been measured as function of two source parameters. The first one is the current
flowing through the grid facing the plasma, the plasma grid (PG), in order to generate the magnetic filter field. The second one is the bias current flowing between the PG and the source
walls. Both the filter field and the bias current influence the fraction of co-extracted electrons, but also the properties of the plasma just in front of the extraction system and the beam properties.
The divergence and the uniformity of the beam have been measured by a beam emission spectroscopy (BES) diagnostic; the detailed analysis of the raw spectra collected by BES led to
describing the beam with two components of different divergence. This concept has been supported by the information given by thermal imaging of the diagnostic calorimeter. Further
support to the proposed beam model has been found in the behavior of the currents flowing in the acceleration system and beamline components; these currents are given by the most divergent (charged) particles of the beam
Spektroskopische Diagnostik von Niederdruckentladungen mit speziellen Verteilungsfunktionen
No full textSpektroskopische Diagnostik von Niederdruckentladungen mit speziellen Verteilungsfunktionen / K. Behringer ; U. Fantz. - In: Deutsche Physikalische Gesellschaft: Verhandlungen der ... Reihe 6. 29. 1994. P14.
Yacora on the Web: Online collisional radiative models for plasmas containing H, H2 or He
No full textYacora on the Web (www.yacora.de) is a web application providing access to collisional radiative models based on the flexible solver Yacora. The main application range is plasma diagnostics in low-pressure plasmas. Available online are three collisional radiative models, namely for atomic hydrogen, molecular hydrogen and helium. This paper gives a brief overview to collisional radiative modeling and to the Yacora solver. The functionality of Yacora on the Web is introduced and the three available models as well as the used input data are presented and discussed. As application example, the models for atomic and molecular hydrogen are applied for investigating spontaneous emission in ionizing and recombining plasmas. This application shows a very good agreement between measured and calculated emission intensities as well as between plasma parameters from other diagnostics and those derived using Yacora on the Web from optical emission spectroscopy results
Conceptual design of the beam source for the DEMO Neutral Beam Injectors
No full textDEMO(DEMOnstration Fusion Power Plant) is a proposed nuclear fusion power plant that is intended to follow the ITER experimental reactor. The main goal ofDEMOwill be to demonstrate the possibility to produce electric energy from the fusion reaction. The injection of high energy neutral beams is one of the main tools to heat the plasma up to fusion conditions. Aconceptual design of the Neutral Beam Injector (NBI) for theDEMOfusion reactor, is currently being developed by Consorzio RFX in collaboration with other European research institutes. High efficiency and low recirculating power, which are fundamental requirements for the success of DEMO, have been taken into special consideration for theDEMONBI. Moreover, particular attention has been paid to the issues related to reliability, availability, maintainability and inspectability. A conceptual design of the beam source for theDEMONBI is here presented featuring 20 sub-sources (two adjacent columns of 10 sub-sources each), following a modular design concept, with each sub-source featuring its radio frequency driver, capable of increasing the reliability and availability of theDEMONBI. Copper grids with increasing size of the apertures have been adopted in the accelerator, with three main layouts of the apertures (circular apertures, slotted apertures and frame-like apertures for each sub-source). This design, permitting to significantly decrease the stripping losses in the accelerator without spoiling the beam optics, has been investigated with a self-consistent model able to study at the same time the magnetic field, the electrostatic field and the trajectory of the negative ions. Moreover, the status on theR& D carried out in Europe on the ion sources is presented.SP
Evaluation of power transfer efficiency for a high power inductively coupled radio-frequency hydrogen ion source
No full textEfficiency of Cs-free materials for negative ion production in H<sub>2</sub> and D<sub>2</sub> plasmas
No full textSimultaneous measurements of work function and H<sup>–</sup> density including caesiation of a converter surface
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