Observation of an optical anisotropy in the deep glacial Ice at the geographic South Pole using a laser dust logger

Abstract

We report on a depth-dependent observation of a directional anisotropy In the recorded Intensity of backscattered light as measured by an oriented laser dust logger. The measurement was performed In a drill hole at the geographic South Pole about a kilometer away from the IceCube Neutrino Observatory. The drill hole has remained open for access since the SPiCEcore collaboration retrieved a 1751m Ice core. We find the anisotropy axis of 1263 as measured below 1100m to be compatible with the local flow direction. The observation Is discussed In comparison to a similar anisotropy observed In data from the IceCube Neutrino Observatory and favors a birefringence-based scenario over previously suggested Mie-scattering-based explanations. In the future, the measurement principle, when combined with a full-chain simulation, may have the potential to provide a continuous record of fabric properties along the entire depth of a drill hole.