Abstract
We have observed a new phenomenon in the pinched phase of an argon collapsing-gas-shell Z-pinch. An x-ray streak camera was used to observe the hard-x-ray (>1 keV) emission as a function of Z position and time. The streak photographs show that at a given Z location the x-ray emission "winks." We have developed a model based upon runaway electrons interacting with ions to explain this phenomenon.