Aachen PK 2003 – wissenschaftliches Programm
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P: Plasmaphysik
P 4: Poster I
P 4.28: Poster
Montag, 17. März 2003, 17:45–19:15, Foyer
Investigating impurity transport in TEXTOR using wavelength selective soft x-ray tomography — •Maarten De Bock1, Manfred von Hellermann1, and Leonid Shmaenok2 — 1FOM Institute of Plasma Physics ‘Rijnhuizen’ — 2Phystex
Impurities are an ambiguous matter in tokamak plasmas. In the core they poison the plasma – by impurity accumulation – , while in the edge regions they can have a positive effect – e.g. the Radiative Improved modes. The aim of the new soft x-ray tomography system on the medium sized tokamak TEXTOR is to monitor the time evolution of 2 dimensional density profiles for several impurity ions.
The system constructs a 2D line emission profile using the images of 5 pinhole cameras followed by a tomographic reconstruction. The specific emission lines are selected by multi layer mirrors (MLM). Several ionization states of the elements Ar, Ne, B, C and O can be selected (wavelength range: 0.3 – 12.5 nm). The time resolution of the tomographic system is 20 ms in continuous mode, and up to 1 ms in burst mode.
Using additional data (electron temperature, electron density and atomic data) we can calculate the impurity density profiles out of the line emission profiles. An overview of the system, tomographic methods and first results are presented.