Electron multiplication and avalanching in nanovoids at the initial stage of nanosecond discharge in liquid water
| Autoři | |
|---|---|
| Rok publikování | 2021 |
| Druh | Článek v odborném periodiku |
| Časopis / Zdroj | Plasma Sources Science and Technology |
| Fakulta / Pracoviště MU | |
| Citace | |
| www | https://doi.org/10.1088/1361-6595/abff73 |
| Doi | http://dx.doi.org/10.1088/1361-6595/abff73 |
| Klíčová slova | Geant4-DNA; electron multiplication; plasma in liquids; nanosecond discharge in liquid water |
| Popis | This work presents a study on electron multiplication in cylindrical nanovoids formed in liquid water due to strong pulsed external electric fields. The state-of-the-art simulation toolkit Geant4-DNA is used to describe electron interactions in liquid water. Scaling laws for electron propagation are introduced, concluding that the product of the electric field strength E and the cavity radius R is a suitable parameter to compare simulation results for different values of E and R, and 1/R scaling is proposed for space and time variables. It is shown that the electron avalanche can grow inside of the nanovoid if E · R > 19.4 eV. The avalanche growth is fed by the emission of the secondary electrons from the surface of the nanovoid. This electron avalanche can also provide a higher total ionization yield along the nanovoid than the simple direct flight of electrons through the nanovoid length. Characteristic electron multiplication timescale and avalanche velocity are determined. Multiplication timescale is shown to be of the order of 1 ps or shorter for electron-multiplying conditions. The velocity of the electron avalanche is about 2.8 × 106 m s-1. The multiplication timescale and the avalanche velocity are consistent with recent experimental observations on nanosecond discharge initiation in liquid water. |
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