My research characterizes diffuse ionized gas across a wide range of astrophysical contexts, from the heliosphere and very local interstellar medium to the intergalactic medium and other galaxies. I use a combination of theory and observation to study this diffuse gas, including data from the Voyager Interstellar Mission, Galactic radio pulsars, and extragalactic fast radio bursts. I am also broadly interested in using our understanding of diffuse plasmas everywhere to inform studies of compact objects, including the extreme sources of fast radio bursts and the supermassive black hole binaries probed by pulsar timing arrays.