Prospects for a radio air-shower detector at South Pole

IceCube is currently not only the largest neutrino telescope but also one of the world's most competitive instruments for studying cosmic rays in the PeV to EeV regime where the transition from galactic to extra-galactic sources should occur. Further augmenting this observatory with an array of radio sensors in the 10-100 MHz regime will additionally permit observation of the geomagnetic radio emission from the air shower. Yielding complementary information on the shower development a triple-technology array consisting of radio sensors, the ground sampling stations of IceTop and the in-ice optical modules of IceCube, should significantly improve the understanding of cosmic rays, as well as enhance many aspects of the physics reach of the observatory. Here we present first results from two exploratory setups deployed at the South Pole. Noise measurements from data taken in two consecutive seasons show a very good agreement of the predicted and observed response of the antennas designed specifically for this purpose. The radio background is found to be highly dominated by galactic noise with a striking absence of anthropogenic radio emitters in the frequency band from 25-300 MHz. Motivated by the excellent suitability of the location, we present first performance studies of a proposed Radio Air-Shower Test Array (RASTA) using detailed MonteCarlo simulation and discuss the prospects for its installation.