Nanoparticle plasma ejected directly from solid copper by localized microwaves

A plasma column ejected directly from solid copper by localized microwaves is studied. The effect stems from an induced hotspot that melts and emits ionized copper vapors as a confined fire column. Nanoparticles of similar to 20-120 nm size were revealed in the ejected column by in situ small-angle x-ray scattering. Optical spectroscopy confirmed the dominance of copper particles in the plasma column originating directly from the copper substrate. Nano- and macroparticles of copper were verified also by ex situ scanning electron microscopy The direct conversion of solid metals to nanoparticles is demonstrated and various applications are proposed. 0 2009 American Institute of Physics. [doi: 10.1063/1.3259781]