A GPU-based Calculation Method for Near Field Effects of Cherenkov
  Radiation Induced by Ultra High Energy Cosmic Neutrinos
  The radio approach for detecting the ultra-high energy cosmic neutrinos has
become a mature field. The Cherenkov signals in radio detection are originated
from the charge excess of particle showers due to Askaryan effect. The
conventional way of calculating the Cherenkov pulses by making Fraunhofer
approximation fails when the sizes of the elongated showers become comparable
with the detection distances. We present a calculation method of Cherenkov
pulses based on the finite-difference time-domain (FDTD) method, and attain a
satisfying effeciency via the GPU- acceleration. Our method provides a
straightforward way of the near field calculation, which would be important for
ultra high energy particle showers, especailly the electromagnetic showers
induced by the high energy leptons produced in the neutrino charge current
interactions.
