NEW DESIGN OF THE GYROTRON USED FOR ECRH EXPERIMENTS ON TORE SUPRA
C. Darbos(a), S. Alberti(b), A.
Arnold(d), D. Bariou(c), F. Bouquey(a), J.
Clary(a), J.P. Hogge(b), M. Lennholm(a), C.
Liévin(c), R.Magne(a), M. Thumm(d)
(a) Association Euratom-CEA, CEA/DSM/DRFC, CEA-Cadarache,
13108 Saint Paul Lez Durance, France
(b) Association Euratom-Confédération Suisse, Centre de Recherches en Physiques des Plasmas, EPFL-Ecublens, 1015 Lausanne, Switzerland
(d) Association Euratom-FZK, IHM, Postfach 3640, 76021 Karlsruhe, Germany
email : caroline.darbos@cea.fr
For ECRH (Electron Cyclotron Resonance Heating)
and current drive experiments on the tokamak Tore Supra, gyrotrons have been
developed thanks to a collaboration between TED (Thales Electron Devices),
Association Euratom-Confédération Suisse, Association Euratom-FZK and
Association Euratom-CEA.
Limitations on pulse length (about 110 s) have
been observed on the first series gyrotron during the tests in Cadarache [1],
which have been explained by the overheating of internal components of the tube
due to its inadequate cooling. Moreover, the geometry of the launcher seems to
be the origin of the oscillation of spurious frequencies inside and at the
output of the gyrotron, possibly leading to degraded performances.
To improve the gyrotron, new studies between the same partners have been made and a new tube has just been built by TED, mainly with a new cooling system and a different geometry for the launcher. The very first tests are just starting until the factory acceptance tests planned on January 2004, followed by long pulse testing in Cadarache (up to 600 s). All the results obtained will be presented, as well as a full description of the modifications made on this new gyrotron, in comparison with its previous design.
References
[1] Operation of the 118 GHz Very Long Pulse Gyrotron for the ECRH Experiment on Tore Supra, C. Darbos et al., EC12, Aix-en-Provence, 2002.