Magnetic Fields and Cosmic Rays in Galaxy Cluster Cooling Flows

Cooling flows are regions where the importance of non-thermal intracluster medium components such as magnetic fields and cosmic rays may be strongest within a galaxy cluster. They are also regions where such components are best detectable due to the high gas density which influences Faraday rotation measurements of magnetic fields and secondary particle production in hadronic interactions of cosmic ray nuclei with the ambient thermal gas. New estimates of magnetic fields in cooling flow and noncooling flow clusters are presented, which are based on a newly developed Fourier analysis of extended Faraday rotation maps. We further present new constraints on the cluster cosmic ray proton population using radio and gamma-ray observations of cluster cooling flows, which are especially suited for this purpose due to their high gas and magnetic energy densities. We argue that radio synchrotron emission of cosmic ray electrons generated hadronically by cosmic ray protons is a very plausible explanation for the radio mini-halos observed in some cooling flows.