STRONG ANOMALOUS EMISSION FROM HE-LIKE AND H-LIKE NE IN SHORT-PULSE LASER-DRIVEN PLASMAS

We observe strong emission-from the 1s(2)-1snp Rydberg series in He-Li ke Ne and from the Lyman-cu transition in H-like Ne. These emissions a re observed when 1.05-mu m light in a 600-fs laser pulse is focused in to the dense, localized output of a pulsed supersonic nozzle. The maxi mum focal irradiance of our laser was measured at full power in vacuum to be 1.1 X 10(18) W/cm(2) Although emissions from lower charge state s such as Ne6+ and Ne7+ closely follow rates predicted by tunneling th eory, emissions from Ne8+ and Ne9+ are observed at irradiances 2 order s of magnitude below tunneling theory estimates. We discuss the origin s of these anomalously high charge states and the implications to the development of short-pulse, ultrahigh-brightness x-ray sources. (C) 19 96 Optical Society of America