Jet ejecta mass upon oblique impact

Theoretical models in the jetting regime for symmetric and asymmetric impact of thin plates predict the mass and velocity of jetted material upon oblique impact. However, experimental constraints on the amount of material which form jets upon oblique impact are unstudied. A series of preliminary experiments were conducted in which tungsten (W) flyer plates at speeds of 1.5 to 2.0 km/s were obliquely impacted into carbon (C) targets at 30° in the regime of jetting, yielding radiation temperatures in the ~3200 K range. Both framing camera and flash X-ray imaging were conducted. Broad cm-sized craters induced by jet ejecta on 2024 Al witness plates were used to infer jet mass. We infer, from measured witness plate crater volumes, that jet masses in the range of 0.01 to 0.06 g are produced by a 32 mm diameter, 6 mm thick W impactor. This is about one to two orders of magnitude less than those calculated from present theoretical models. In contrast, in refractory material experiments the mass of gabbro ejecta trapped in styrofoam is 0.52 g which is similar to that calculated.