5-9 September 2016
Prague Congress Centre
Europe/Prague timezone

P1.027 Electron Emission Under Uniform Magnetic Field of Materials For Fusion And Spatial Applications

5 Sep 2016, 14:20
1h 40m
Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Foyer 2A (2nd floor), 3A (3rd floor)

Prague Congress Centre

5. května 65, Prague, Czech Republic
Board: 27
Poster B. Plasma Heating and Current Drive P1 Poster session

Speaker

Nicolas Fil (Engineering)

Description

The power handling of RF components can be limited   by a resonant process known as Multipactor effect. Multipactor can be fatal   to microwave systems in space communication payloads or in experimental fusion devices. Multipactor simulations   are used to predict voltage thresholds but the results highly depends on the electron emission properties of the RF components materials. Moreover, both space and fusion applications devices deal with DC magnetic fields. These are generated by permanent magnets in satellites while toroidal and poloidal coils create an intense magnetic field in fusion reactors. In order to improve understanding and predictability of multipactor effect, materials electron emission measurements under uniform DC magnetic field is carried on. An experimental test-bed has been developed to measure electron emission for fusion materials such as copper and alumina with TiN flash on its surface. Our goal is to measure the Total Electron Emission Yield (TEEY) used as input in multipactor simulations. We work under a 10-6 Pa pressure and an electron gun with an energy range between 1 eV and 2000 eV. A 41mm-diameter solenoid coil made with copper generates an uniform magnetic field perpendicular to the sample surface. TEEY measurements have been made on uncontrolled   surface morphology samples to understand the influence of the magnetic field on electron emission. Then specific morphology surface samples have been used to reduce the electron emission using the electron motion induced by the uniform magnetic field. The multipactor sensitivity to these fields has been thus characterized considering samples roughness and magnetic field direction and strength. In this paper we describe the development of the test-bed which allows us to measure electron emission for fusion materials under uniform DC magnetic fields in order to improve our understanding and the predictability of multipactor effect.

Co-authors

Jerome Puech (Radio-Frequency Department, CNES, the French Space Agency, 18 avenue Edouard Belin, 31000 Toulouse, France) Julien Hillairet (Engineering, In-vessel components and Projects Department, CEA, French Alternative Energies and Atomic Energy Commission, 13108, Saint Paul lez Durance, France) Mohamed Belhaj (Spatial Environment Department, ONERA, the French Aerospace Laboratory, 2 avenue Edouard Belin, 31000 Toulouse, France) Nicolas Fil (Engineering, In-vessel components and Projects Department, CEA, French Alternative Energies and Atomic Energy Commission, 13108, Saint Paul lez Durance, France)

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