Shock pressure attenuation in water ice at a pressure below 1 GPa

Shock pressure attenuation in water ice was studied at an impact pressure b elow 1 GPa and a temperature of 255 K. The observed shock wave showed a mul tiple shock wave structure: A precursor wave was followed by a main wave, w hich had a longer rise time and higher amplitude. The Hugoniot elastic limi t (HEL) of water ice was measured to be in the range from 0.1 to 0.3 GPa wh en associated with precursor waves traveling at 3.86 km/s. The peak amplitu de of the main wave P-m was observed to decrease with its propagation x fro m 3 to 60 mm (from 0.4 to 8 times as large as a projectile radius) in two s eries of experiments in which initial shock pressures P-i at the impact poi nt were 0.60 and 0.87 GPa. The P-m was described as the power law relation P-m/P-i = (x/2.6 mm)(-0.89). The precursor wave disappears as the P-m atten uated to a pressure < 0.1 GPa. The measured wave profiles were used to calc ulate the loading path of water ice in shock compression between the HEL an d 0.6 GPa. The loading path obtained by Lagrangian analysis was closely con sistent with previous Hugoniot data regarding water ice.