Speaker
Dr
Bernardo Zurro
(Laboratorio Nacional de Fusión, CIEMAT)
Description
Impurity confinement time has been studied as a function of charge and mass of the impurity ions by using laser blow-off injection of trace impurities into electron cyclotron heated discharges of the TJ-II heliac. Impurities ranging from low-Z (LiF) to high-Z (W) are injected. The experiment has been carried out at constant density (5x10^19 m^-3), injected power (500 kW) and magnetic configuration. A lower impurity confinement time (~5 ms) in the plasma core as compared with the plasma edge (~10 ms) is revealed from soft X-ray analysis and tomographic reconstruction of signals from a fast bolometer array. A dependence of impurity confinement with charge seems to be the most probable explanation of the results obtained; this is supported by the analysis of spectrally resolved data in the VUV range. The results seem qualitatively consistent with the dependence of impurity neoclassical transport on the background radial electric field. The results obtained will be discussed in the context of other stellarator and tokamak experiments on trace impurity transport.
| Country or International Organisation | Spain |
|---|---|
| Paper Number | EX/P4-43 |
Author
Dr
Bernardo Zurro
(Laboratorio Nacional de Fusión, CIEMAT)
Co-authors
Dr
Alfonso Baciero
(Laboratorio Nacional de Fusión, CIEMAT)
Dr
David Rapisarda
(Laboratorio Nacional de Fusión, CIEMAT)
Dr
Diana Baião
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa)
Dr
Eduardo De la Cal
(Laboratorio Nacional de Fusión, CIEMAT)
Dr
Eric M. Hollmann
(University of California San Diego)
Dr
Francisco Medina
(Laboratorio Nacional de Fusión, CIEMAT)
Dr
Ignacio Pastor
(Laboratorio Nacional de Fusión, CIEMAT)
Dr
José Luis Velasco
(Laboratorio Nacional de Fusión, CIEMAT)
Dr
Kieran Joseph McCarthy
(Laboratorio Nacional de Fusión, CIEMAT)
Dr
María Antonia Ochando
(Laboratorio Nacional de Fusión, CIEMAT)
