Interferometric measurement of physical phenomena during the implosion phase of a puff-on-puff Z-pinch load on Double-EAGLE

Theoretical studies have predicted that the disruptive role of the Rayleigh-Taylor (R-T) instability on the current conduction and implosion characteristics of annular Z-pinch loads will be mitigated by mass accretion if uniform fill or multiple annular shell loads are used. Holographic interferometry was used to study these physical processes during the implosion phase of puff-on-puff loads on a terawatt accelerator. Both axial (r-z) density perturbation and azimuthal (r-(theta)) filamentation modes of the R-T instability were observed. Significant ionization (Z~3-10) of the inner gas puff atoms was observed below the anode grid before the outer puff had imploded to this radial position. Radiation hydrodynamic calculations indicate that photoionization by radiation from the outer current carrying shell could not account for this ionization. Current flowing on the inner gas puff could be the source of this ionization. The effect of these physical processes on the radiation yield from zpinches warrants further investigation.