The impact of non-linear wave propagation on the observation of cosmic neutrinos

Supermassive black holes and colliding neutron stars are amongst the most violent and energetic objects in the Universe. They can be studied through the elementary particles that they accelerate and hurl into space. Amongst them are neutrinos, ghost-like particles that can penetrate deep into the Earth before interacting. Neutrinos that have
a collision kilometers deep in the South Pole ice layer can be detected because they emit a short radio flash. Arrays of radio antennas buried in the ice can record these flashes. Because neutrinos of the highest energies are extremely rare, a neutrino radio array needs to cover a volume of 100 cubed kilometers of ice. To optimize the sensitivity and performance of such an array the propagation of the radio waves needs to be understood in high detail. Data from prototype detector stations indicate that this propagation is much more complicated than expected. Radio waves do not just
travel in straight lines but can reach the antennas via multiple paths depending on the characteristics of the ice and snow layers. We will study these exotic forms of radio propagation to improve the reconstruction capabilities of the next-generation cosmic neutrino experiments and increase their sensitivity to the cosmic neutrino flux.