Ice detectors listen to the radio voices of cosmic particles express
Neutrinos are ghost particles: predicted by the Standard Model, they barely interact with matter. Catching them is like trying to hear a whisper in the roar of a waterfall. The ARA and RNO-G detectors, frozen into the ice of Antarctica and Greenland, act like ears, picking up radio bursts that race outward through the ice at the speed of light when a particle hits. Transparent to radio waves like glass to light, the ice allows the signal to be heard from kilometers away. But the roar isn't just from neutrinos: cosmic rays constantly bombard the Earth and produce similar bursts. To tune out this noise, physicists used the FAERIE simulation. It recreated a particle's path from the atmosphere to the glacier and described its 'signature': the direction of the radio waves, arrival time, and strength. The model ran for weeks on supercomputers, although the burst lasts billionths of a second. These data teach detectors not to confuse neutrinos with cosmic rays. Then the planet's radio ear will pick up the distant voices of black holes and stellar explosions, encoded in the radio spectroscopy of icy showers.
Original abstract
as written by the authors arXiv:2601.06409v1
To detect ultra-high-energy neutrinos, experiments such as ARA and RNO-G target the radio emission induced by these particles as they cascade in the ice, using deep in-ice antennas at the South Pole or in Greenland. In this context, it is essential to first characterize the in-ice radio signature from cosmic-ray-induced particle showers, which constitute a primary background for neutrino detection, and represent the fist in-situ detection of in-ice particle cascades with radio antennas. This characterization will help validate the detection principle and assist in calibration. To achieve this goal, we used FAERIE, the "Framework for the simulation of Air shower Emission of Radio for in-Ice Experiments", that combines CoREAS and GEANT4 to simulate the radio emission of cosmic ray showers deep in the ice. Using this tool, we analyze in-ice radio signatures of cosmic-ray showers, including polarization, timing, and radiation energy, as well as their dependence on shower parameters. These insights will facilitate the first cosmic-ray detections and improve cosmic-ray/neutrino discrimination.
Antarctic ice at depths of 1–2 km is more transparent to radio waves than air: a signal can travel ten kilometers with almost no loss.