Explosive Electron Emission Ignition at the “W-Fuzz” Surface Under Plasma Power Load

The essentially nonstationary explosivelike character of erosion-emission processes was revealed by analyzing the plasma action onto a nanostructured W-fuzz surface. It was found that such a fine structure of the surface promotes a local ecton-process ignition by plasma action. The dense W-plasma production time is much less than that of a typical fusion-device first-wall transient-event edge localized mode (ELM) power load. The W-plasma density substantially exceeds that of the incident plasma and leads to intense growth of the electric field and strong emission buildup. Therefore, at the ELM power load, the electric field and emission current density (in the W-plasma-wall sheath) can achieve tens of megavolts per centimeter and 100 MA/cm2or higher due to collective processes driven by an intense emission beam. The strong volume heating by Joule energy release occurs due to the intense emission current density that leads to electric explosion of other W-fuzz nanowire layers.