Christophe Lievin

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In the first part of this paper, the status of the 140-GHz continuously operated gyrotrons with an output power of 1 MW for the stellarator Wendelstein 7-X will be described. With the first series tube, an output power of 1000 kW has been achieved in short pulse operation (milliseconds) with an electron beam current of 40 A, and of 1150 kW at 50 A. With a(More)
High-frequency gyrotrons with high output power are mainly used for microwave heating and current drive in plasmas for thermonuclear fusion. The development of high-power gyrotrons in continuous wave (CW) operation has been in progress for several years in a joint collaboration between different European research centers and an industrial partner. The(More)
The first prototype of the EU 170 GHz/2 MW/CW coaxial cavity gyrotron for ITER has been tested in the frame of a collaboration between European Research Institutions (EGYC <sup>1</sup>) supported by Fusion for Energy (F4E). The experiments showed (i) the limitation of the operating parameters range to a low efficiency domain, and (ii) a voltage stand-off(More)
In the reference ECH design, ITER requires a total of 20 MW/CW power at 170 GHz using gyrotrons with a unit power of 1 MW. A higher power per unit (2 MW/gyrotron) would result in a strong reduction of the cost of the whole ECRH system, and would also relax the room constraints on the launcher antenna design. The high power capability of coaxial cavity(More)
For future nuclear fusion reactors it is desirable to increase the RF power per gyrotron tube used for electron cyclotron resonance heating. Using gyrotrons with higher output power will reduce their overall number and the number of super-conducting magnets required. In this work the feasibility of a 4 MW 170 GHz continuous wave (CW) coaxial-cavity gyrotron(More)
A 10 MW, 140 GHz ECRH system with a pulse duration of 30 minutes is currently under construction for the stellarator W7-X at Greifswald. The RF power will be provided by 10 gyrotrons. A European collaboration has been established to develop and build 9 (out of 10) tubes each with an output power of 1 MW for continuous wave (CW) operation. This contribution(More)
A collaborative effort between European research associations and Thales Electron Devices (TED) has been launched by the European Fusion Development Agreement (EFDA) in 2003, aiming at the development of an industrial 170GHz/2MW/CW coaxial cavity gyrotron. The first prototype, although designed to be CW compatible is expected to reach 2MW/ls and is(More)
The development of high power gyrotrons in continuous wave operation for heating of plasmas used in nuclear fusion research has been in progress for several years in a collaboration between different European research institutes and industrial partners. The 140 GHz gyrotron is designed for an output power of 1 MW in continuous wave operation and is operated(More)
Summary form only given. A 10 MW ECRH system is currently under construction for the stellarator W7-X which will be built up and operated by IPP in Greifswald, Germany. The RF power will be provided by 10 gyrotrons. A European collaboration has been established to develop and build the 10 gyrotrons each with an output power of 1 MW for continuous wave (CW)(More)
The development of high power gyrotrons (118 GHz, 140 GHz) in continuous wave operation (CW) has been in progress for several years in a joint collaboration between different European research institutes and industrial partners. In this frame, two 140 GHz prototype gyrotrons for CW operation had been constructed and tested at the Forschungszentrum(More)