Ultrafast x-ray imaging of pulsed plasmas in water

Abstract

Ultrafast x-ray imaging is useful for diagnosing a wide range of nanosecond-time scale physical processes, particularly those concealed by optical emission or otherwise opaque objects. Here we use the ultrafast x-ray imaging facilities at Argonne National Laboratory's Advanced Photon Source to interrogate nanosecond-pulsed single-electrode plasma initiation processes in water (+25 kV, 10 ns, 5 mJ), with supporting nanosecond optical imaging and x-ray diffraction computational model. These results clearly resolve narrow (∼10μm) low-density plasma channels during initiation time scales typically obscured by optical emission. This multiphase environment is not well described in literature, and these experimental results appear to be inconsistent with prevailing breakdown initiation hypotheses. This work also proposes this plasma process as a cheap, compact, and repeatable benchmark imaging target with hypersonic phenomena (29.1 km/s) and very high-power densities (1TW/cm2), useful for the development of next-generation ultrafast imaging of inertial confinement fusion and other nanosecond processes of interest.