Jetting during oblique impacts of spherical impactors

TL;DR

This study uses simulations to analyze how impact angle influences jetting during oblique impacts, revealing that oblique impacts generally produce more jetted ejecta than vertical impacts, with the origin of ejecta depending on impact angle.

Contribution

It provides new insights into the dependence of jetting behavior on impact angle and impact velocity using detailed shock physics simulations.

Findings

Oblique impacts produce more jetted ejecta than vertical impacts.

The origin of jetted material varies with impact angle.

Jetted materials are distributed downrange of the impactor.

Abstract

During the early stages of an impact a small amount material may be jetted and ejected at speeds exceeding the impact velocity. Jetting is an important process for producing melt during relatively low velocity impacts. How impact angle affects the jetting process has yet to be fully understood. Here, we simulate jetting during oblique impacts using the iSALE shock physics code. Assuming both the target and impactor have the same composition (dunite), we examine the jetted material which exceeds the impact velocity. Our results show that oblique impacts always produce more jetted ejecta than vertical impacts, except for grazing impacts with impact angles $< 15^{\circ}$. A 45$^{\circ}$ impact with an impact velocity of 3 km/s produces jetted material equal to $\sim$ 7 \% of the impactor mass. This is 6 times the jetted mass produced by a vertical impact with similar impact conditions. We also find that the origin of jetted ejecta depends on impact angle; for impact angles less than 45$^{\circ}$, most of the jet is composed of impactor material, while at higher impact angles the jet is dominated by target material. Our findings are consistent with previous experimental work. In all cases, jetted materials are preferentially distributed downrange of the impactor.