Speaker
Description
The Askaryan effect in dense dielectric media allows for the detection of ultrahigh energy (UHE) neutrinos and cosmic rays via their radio-wavelength emissions in polar ice. In-ice radio detectors like ARA, RNO-G, and the proposed IceCube-Gen2 radio array receive signals that have traveled over kilometer scales, at which distance the medium's depth-dependent refractive index has a significant effect on propagation direction. In this talk, we study how these ice effects impact ray focusing and visible ice volume. We also use travel-time maps, which contain pre-calculated propagation times to a receiver from possible in-ice interaction locations, to account for the varying refractive index when reconstructing signal source locations. However, current methods for travel-time map generation rely on numerical root-finding, making them too computationally expensive to facilitate iterative calibration of model parameters. We suggest the Fast Marching Method as an alternative to point-by-point root-finding, and demonstrate its comparative speed and accuracy when applied to the radio-ice problem.