Measurements of the Electric Field in a Resonant Microwave Cavity for Dark Matter Axion Searches

The Axion Dark Matter Experiment at High Frequency (ADMX HF) is an experiment in search for the Axion, a highly motivated dark matter candidate. The Axion can be measured by looking for its conversion to detectable microwave photons in a resonant microwave cavity that is in the presence of a large magnetic field. The power generated from axion-photon conversions in the cavity is a function of the electric field structure of the particular mode that the cavity is tuned to. Here I will present on techniques to directly measure the electric field of a microwave cavity by perturbing it with a small dielectric bead (also known as a ``bead-pull'' measurement) and comparing it with the natural resonant frequency. These results can be compared directly to expected field patterns from simulation. I also will present on plans for future measurements of cavities with tuning rods to measure mode localizations near the TM010 and higher order modes.