The effect of shock waves on diamagnetic fabrics

Abstract

Para-and ferro-magnetic fabrics are known to provide essential clues for understanding impact cratering processes. However, research on the effects of shock waves on diamagnetic fabrics is lacking. We, therefore, conducted a hypervelocity impact experiment on a block of diamagnetic Taunus quartzite and studied the changes in diamagnetic fabrics. In the crater subsurface, the reorientation of the diamagnetic fabrics is concentrated in a zone of ˜4 projectile diameters (25 mm) width directly below the point of impact. Higher reorientation in this zone indicates the concentration of damage. We argue that although the shockwaves traversed through the target with a hemi spherical wavefront, the damage was concentrated directly below the point of impact.Another important observation is that the weak shock waves have changed the diamagnetic parameters. The bulk susceptibility has increased overall, while the corrected degree of anisotropy (P') and the shape parameter (T) have increased in the crater subsurface but have decreased at the target surface. We propose that the variable response of P' and T could be due to the difference in incident angle subtended by the shock wave on the diamagnetic foliation at the target surface (c. 34°) and in the subsurface (c. 54°). These results, thus, show that the changes in diamagnetic fabrics can be used as a proxy for plastic deformation caused by shock waves at low peak pressures.