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P: Plasmaphysik
P 1: Magnetic Confinement and Plasma Wall Interaction
P 1.7: Vortrag
Montag, 2. April 2001, 18:10–18:25, 2053
Measurements of fluctuations in the electron density in the edge plasma of the tokamak TEXTOR-94 — •M. Bruchhausen1, G. Kocsis2, A. Pospieszczyk1, B. Schweer1, and S. Zoletnik2 — 1Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Assoziation, Trilateral Euregio Cluster, D-52425 Jülich — 2KFKI Research Institute for Particle and Nuclear Physics, P.O.B 49, H-1525, Budapest, Hungary
Atomic beams – and especially lithium beams – are a powerful tool for the investigation of fluctuations of the electron density in fusion edge plasmas. Such beams are generated either by acceleration of Li ions by means of a high voltage (typically 10−100 kV) and subsequent neutralisation or by means of a thermal source leading to particle energies of typically 50 meV. Laser blow-off generated beams in comparison feature particle energies in the order of 10 eV. Because of its higher speed the LBO beam can penetrate deeper into the plasma than a thermal beam. Even so, it does not have the major disadvantage of the high energetic beam that covers the distance of several correlation lengths during one relaxation time which leads to carry-off effects. This means that LBO has – even if it is a pulsed system – some advantages compared to the other methods. Therefore several measurements have been performed on TEXTOR-94 with a repetitive LBO system (repetition frequency ≤ 20 Hz). They are to be compared with the results obtained with a thermal Li-beam shown in [1] and shall extend them further into the plasma.
[1] A.Huber et al. J.Nucl.Mater. 266-269 (1999) 546-551