Author/Authors :
Urbanus، نويسنده , , W.H and Bratman، نويسنده , , V.L and Bongers، نويسنده , , W.A and Caplan، نويسنده , , M and Denisov، نويسنده , , G.G. and van der Geer، نويسنده , , C.A.J. and Manintveld، نويسنده , , P and Militsyn، نويسنده , , B and Oomens، نويسنده , , A.A.M and Poelman، نويسنده , , A.J and Plomp، نويسنده , , J and Pluygers، نويسنده , , J and Savilov، نويسنده , , A.V. and Smeets، نويسنده , , P.H.M and Sterk، نويسنده , , A.B and Verhoeven، نويسنده , , A.G.A، نويسنده ,
Abstract :
The Fusion-FEM experiment, a high-power, electrostatic free-electron maser being built at the FOM-Institute for Plasma Physics ‘Rijnhuizen’, is operated at various frequencies. So far, experiments were done without a depressed collector, and the pulse length was limited to 12 μs. Nevertheless, many aspects of generation of mm-wave power have been explored, such as the dependency on the electron beam energy and beam current, and cavity settings such as the feedback coefficient. An output power of 730 kW at 206 GHz is generated with a 7.2 A, 1.77 MeV electron beam, and 360 kW at 167 GHz is generated with a 7.4 A, 1.61 MeV electron beam. It is shown experimentally and by simulations that, depending on the electron beam energy, the FEM can operate in single-frequency regime. The next step of the FEM experiment is to reach a pulse length of 100 ms. The major part of the beam line, the high voltage systems, and the collector have been completed. The undulator and mm-wave cavity are now at high voltage (2 MV). The new mm-wave transmission line, which transports the mm-wave output power from the high-voltage terminal to ground and outside the pressure tank, has been tested at low power.
