  We investigate 3D bow shocks in a highly collisional magnetized aluminum
plasma, generated during the ablation phase of an exploding wire array on the
MAGPIE facility (1.4 MA, 240 ns). Ablation of plasma from the wire array
generates radially diverging, supersonic ($M_S \sim 7$), super-Alfv\'enic ($M_A
> 1$) magnetized flows with frozen-in magnetic flux ($R_M \gg 1$). These flows
collide with an inductive probe placed in the flow, which serves both as the
obstacle that generates the magnetized bow shock, and as a diagnostic of the
advected magnetic field. Laser interferometry along two orthogonal lines of
sight is used to measure the line-integrated electron density. A detached bow
shock forms ahead of the probe, with a larger opening angle in the plane
parallel to the magnetic field than in the plane normal to it. Since the
resistive diffusion length of the plasma is comparable to the probe size, the
magnetic field decouples from the ion fluid at the shock front and generates a
hydrodynamic shock, whose structure is determined by the sonic Mach number,
rather than the magnetosonic Mach number of the flow. 3D simulations performed
using the resistive magnetohydrodynamic (MHD) code GORGON confirm this picture,
but under-predict the anisotropy observed in the shape of the experimental bow
shock, suggesting that non-MHD mechanisms may be important for modifying the
shock structure.
