  Spark discharges induce a complex flow field consisting of a shock wave at
early times (~ 1 $\mu$ s), a pair of vortex rings, and a hot gas kernel. The
vortex rings entrain ambient gas into the hot gas kernel and control its
cooling and expansion. In this work, we investigate the shock wave's
contribution in producing the vortex ring vorticity. We analyze high-speed (700
kHz) schlieren images of the shock wave for a range of electrical energies to
measure the shock properties and estimate shock velocity and curvature. These
measurements are combined with a model to calculate the vorticity generated.
The measurements show that the highest vorticity is generated near the peak
shock curvature location, and the shock curvature and strength increase with
electrical energy deposited. A comparison of the vorticity estimated from the
model to vorticity measurements from stereoscopic particle image velocimetry
shows the results to be statistically equivalent. This suggests that the shock
curvature and velocity contribute to the vortex rings induced by spark
discharges.
