6:15 PM - 7:30 PM
[PPS21-P19] Measurements of the density, permittivity, and crack distribution in basalt targets based on the impact experiment
We performed the impact experiment by using the two-stage light-gas (hydrogen) gun at JAXA on December 2014. The spherical stainless projectiles (0.32 cm in diameter and 0.133 g in mass) were launched at the velocities of 3.5, 4.5, 5.5, 6.5 km/s to investigate the impact velocity dependency and impacted on the basalt targets of 20 cm×20 cm×10 cm. We repeated the impact experiment twice for each impact velocity in order to confirm the repeatability. Next, we drilled core samples (2.5 cm in diameter and 8-10 cm in length) from the basalt targets along a horizontal and depth directions in order to investigate the effect of anisotropic crack on the permittivity. This investigation gives us the opportunity of the verification based on the effective medium theory [e,g., Sihvola, 1988], which supposes the effect of anisotropic crack on the permittivity. Finally, we sliced the core sample each of ~4 mm in thickness and polished the surface of sliced samples to measure permittivity and surface crack distribution.
We estimated the density of the sliced sample from the measurements of its mass and volume, and investigated the crack fraction by scanning the surface of the sliced thick sample. The permittivity of the sliced thick sample was measured at 5 MHz by using the permittivity measurement system (TOYO Technica Corporation: Type-1260 impedance analyzer and Type-12962A interface) for measuring the permittivity. In the presentation, we will report the initial analysis result of the sliced samples.
Acknowledgement: This study was supported by ISAS/JAXA as a collaborative program with the Space Plasma Laboratory.