Analysis of secondary emission mechanism in electron avalanches propagating in cylindrical nanoruptures in liquid water

0555685 - ÚFP 2022 GB eng J - Journal Article
Bonaventura, Z. - Bílek, Petr - Tungli, J. - Šimek, Milan
Analysis of secondary emission mechanism in electron avalanches propagating in cylindrical nanoruptures in liquid water.
Plasma Sources Science & Technology. Roč. 31, č. 3 (2022), č. článku 035003. ISSN 0963-0252. E-ISSN 1361-6595
R&D Projects: GA ČR(CZ) GA18-04676S
Institutional support: RVO:61389021
Keywords : cross-sections * vapor * electron multiplication * secondary emission * electrostriction * electron avalanche * water * nanosecond discharge in liquid water
OECD category: Inorganic and nuclear chemistry
Impact factor: 3.8, year: 2022
Method of publishing: Limited access
https://iopscience.iop.org/article/10.1088/1361-6595/ac4ddf

Recently, a bouncing-like mechanism for electron multiplication inside long nano-ruptures during the early stages of nanosecond discharge in liquid water has been proposed in (Bonaventura 2021 Plasma Sources Sci. Technol. 30 065023). This mechanism leads to the formation of electron avalanches within nano-ruptures caused by strong electrostrictive forces. The avalanche propagation is a self-sustaining process: the electrons emitted from the water surface to the cavity support the propagation of the avalanche and the avalanche itself is a source of the parent electrons impinging on the surface of the nano-rupture and causing secondary emission. We analyze the process of the electron secondary emission directly from the simulation results of the electron avalanche propagation. This allow us to perform an in situ study of the secondary emission and related physical processes. We present the results of an extensive parametric study performed using the state-of-the-art simulation toolkit Geant4-DNA for modeling electron-liquid water interactions. It is shown that the typical lifetime of an electron in an avalanche is about 0.1 to 0.2 picoseconds and that the electron experiences about 4 bounces before ending up in liquid water. In addition, it is shown that the secondary electrons are formed in a layer adjacent to the nano-rupture surface that is only a few nanometres thin. The secondary electron velocity distribution at the moment of the electron birth, the velocity space of electrons (re-)emitted from the water, and the velocity space of electrons at the moment of their impact to the cavity surface are analyzed in detail. Electron bouncing and secondary electron generation efficiency are quantified using the secondary emission coefficient, the secondary emission efficiency, and the effective energy consumed to produce new electrons.
Permanent Link: http://hdl.handle.net/11104/0330149