Density Structure of Radiatively-Collapsing Reconnection Layer from Shadowgraphy

We present the first quantitative measurements of the plasma density structure of a reconnection layer during radiative collapse. Magnetic reconnection with strong radiative cooling is ubiquitous across a wide range of astrophysical plasmas. The MARZ (Magnetic Reconnection on Z) experiments at Sandia National Laboratories investigate the key physics of astrophysical reconnection. The MARZ pulsed-power platform consists of two exploding aluminum wire arrays, through which a large current (20 MA, 300 ns rise time) is driven by the Z Machine, generating a radiative reconnection layer. With a laser shadowgraphy imaging diagnostic, we take time-resolved snapshots of the layer. It is challenging to extract quantitative values for density structure; our shadowgraphy data exhibit large intensity variations, caustics, and noise. To make these measurements, we fit the experimental intensity profiles to 100k+ forward-model profiles, computed from a simple parameterized model for layer structure.