title: Long-pulse operation at constant output power and single-frequency mode of a high-power electrostatic free-electron maser with depressed collector.
abstract: The Fusion Free-Electron Maser (FFF) is the prototype of a high-power, tunable source of mm-wave radiation, for use on fusion plasma devices. In previous experiments a net output power of 730 kW at 206 GHz was generated in short pulses. The present experiment has been equipped with a system to recover the charge and energy of the spent electron beam. We present experimental results which show output of mm-wave radiation at constant power level during the full pulse length, as well as single-frequency operation; even though the cavity is highly overmoded; the latter is reached by effective suppression of spurious modes by the feedback system.
authors.affiliation: FOM Institute for Plasma Physics "Rijnhuizen," Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein, The Netherlands.
authors.forename: W H
authors.initials: WH
authors.lastname: Urbanus
authors.forename: W A
authors.initials: WA
authors.lastname: Bongers
authors.forename: V
authors.initials: V
authors.lastname: Bratman
authors.forename: C A J
authors.initials: CA
authors.lastname: Van Der Geer
authors.forename: M F
authors.initials: MF
authors.lastname: Graswinckel
authors.forename: P
authors.initials: P
authors.lastname: Manintveld
authors.forename: B L
authors.initials: BL
authors.lastname: Militsyn
authors.forename: A
authors.initials: A
authors.lastname: Savilov