Michael DuVernois, Principal Investigator

Simulations of High-Energy Cosmic-Ray Air Showers

The Pierre Auger Observatory, under construction in Western Argentina, observes cosmic-ray air shower cascades, which can exceed 1020 eV and 10 billion secondary particles. A University of Minnesota School of Physics and Astronomy group is active in both the construction of the detector and large-scale simulations of the air shower physics.

The principal method of studying extremely high-energy cosmic rays is to study the properties of the shower of particles resulting from the initial impact with molecules in the atmosphere. Such showers of secondary particles (which can number in the billions) are typically simulated with two software packages: mocca, an older fortran code with a long history of comparisons with theory, and aires, a modern fortran and c code with updated physics. In support of the Pierre Auger cosmic-ray observatory, currently under construction to observe the highest energy cosmic rays (E>1020 eV), this group is studying the parallelization and optimization of mocca and aires for large-scale simulations aimed at producing a standard shower library for the experiment.

As one component of the air-shower simulation work of the Pierre Auger Observatory, this group migrated the existing air shower simulation toolkits mocca and aires to the IBM SP and SGI Origin at the Supercomputing Institute. This included studies of the serial use of the air shower simulation code as well as a message passing interface-based multiprocessing implementation of the software. This work provided a potential high-speed environment for producing large numbers of sample air showers to form a library for use in detector calibration efforts.

Research Group

Chihwa Song, Research Associate