Origin of anomalous-polarity ANITA events

Determine the physical origin of the non-inverted-polarity radio events observed by ANITA, beyond the shallow, laterally uniform firn-layering mechanism tested in the spherical-wave stratified-boundary model.

Background

The paper studies radio reflection from spherical, stratified media to test whether shallow firn layers could account for ANITA events whose reflected radio pulses have the polarity expected for direct emission rather than the usual polarity inversion from reflection off higher-index ice.

The calculations show that realistic firn contrasts do not reverse the reflected pulse polarity, thereby constraining—but not resolving—the broader explanation of the anomalous events. The discussion explicitly states that the calculation does not identify their origin.