First high power experiments with the Dutch free electron maser

TitleFirst high power experiments with the Dutch free electron maser
Publication TypeJournal Article
Year of Publication1998
AuthorsA.GA Verhoeven, W.A Bongers, V.L Bratman, M. Caplan, G.G Denisov, G. van Dijk, C.AJ van der Geer, P. Manintveld, A.J Poelman, J. Pluygers, M.Y Shmelyov, P.HM Smeets, A.B Sterk, W.H Urbanus
JournalPhysics of Plasmas
Date PublishedMay
ISBN Number1070-664X

A free electron maser (FEM) has been built as a mm-wave source for applications on future fusion research devices such as ITER, the international tokamak experimental reactor [M. A. Makowski, F. Elio, and D. Loeser, April 97, Proc. 10th Workshop on ECE and ECRH, EC10, 549-559. World Scientific (1998)]. A unique feature of the Dutch fusion-FEM is the possibility to tune the frequency over the entire range from 130 to 260 GHz at an output power exceeding 1 MW. In the first phase of the project, a so-called inverse setup is used. The electron gun is mounted inside the high-voltage terminal. The entire beam line was tested successfully with extremely low loss current, lower than 0.05%. This included the accelerating structure up to 2 MV level and the transport through the undulator. First generation of mm-waves was achieved in October 1997. With an electron beam current around 8 A and an accelerator voltage of 1.76 IMV the mm-wave pulse starts after 3 mu s and lasts for 3 mu s, reaching a maximum saturated peak power level of more than 500 kW at a frequency of 200 GHz. Output power, start-up time, and frequency correspond well with simulation results. (C) 1998 American Institute of Physics.



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