Currently there are two complementary methods for the detection of ultra-high energy cosmic rays (UHECRs): direct particle detection in ground arrays, and indirect observation of secondary emission from the residual gas of excited particles and plasma left when the shower of particles transits the atmosphere. The latter method is now applied only to optical fluorescence of molecular nitrogen, but this is not the only possible emission channel. This group proposes to extend the reach of this latter approach by studying the feasibility of observing ultra-high energy cosmic rays via microwave molecular bremsstrahlung radiation from the extensive air shower ionization produced by these events. To do this, they will deploy the Airshower Microwave Bremsstrahlung Experimental Radiometer (AMBER) array in Argentina for observation of UHECRs in conjunction with the Auger Observatory. A prototype is in operation in Hawaii and has produced results suggesting events of cosmic ray origin. The method has the potential to extend the indirect observation methods to a 100% duty cycle.
The investigators seek a broader impact for the project through a program which partners with the existing QuarkNet center at the Univ. of Hawaii Manoa, to expand current teacher training workshops to include a radio and microwave teaching component, centered on aspects of radio detection of high energy cosmic particles. This teaching and training component will provide opportunities for curriculum development, along with a seed program to deploy small microwave dishes for radio science studies at a subset of high schools in Hawaii, to facilitate improvement in science training for Hawaii's underserved students.
