Origin and nature of the emissive sheath surrounding hot tungsten tokamak surfaces

0536450 - ÚFP 2021 RIV NL eng J - Journal Article
Tolias, P. - Komm, Michael - Ratynskaia, S. - Podolník, Aleš
Origin and nature of the emissive sheath surrounding hot tungsten tokamak surfaces.
Nuclear Materials and Energy. Roč. 25, December (2020), č. článku 100818. E-ISSN 2352-1791
R&D Projects: GA MŠMT(CZ) EF16_013/0001551
EU Projects: European Commission(XE) 633053 - EUROfusion
Institutional support: RVO:61389021
Keywords : Melt motion * Schottky effect * Secondary electron emission * Thermionic emission * Tungsten * Virtual cathode
OECD category: Fluids and plasma physics (including surface physics)
Impact factor: 2.320, year: 2020
Method of publishing: Open access
https://www.sciencedirect.com/science/article/pii/S2352179120300922?via%3Dihub

The accurate description of the emitted current that escapes from hot tungsten surfaces is essential for reliable predictions of the macroscopic deformation due to melt motion induced by fast transient events. A comprehensive analytical electron emission model is developed and its implementation in the particle-in-cell 2D3V code SPICE2 is discussed. The properties of emissive sheaths of present tokamaks, where thermionic emission is strongly suppressed by space-charge effects and by prompt re-deposition, are reviewed for arbitrary magnetic field inclination angles. The unique characteristics of emissive sheaths that emerge during ITER ELMs, where weakly impeded thermionic emission is coupled with field emission and competes with electron-induced emission, are revealed. The first ITER simulations are reported for normal inclinations.
Permanent Link: http://hdl.handle.net/11104/0314225