Dedicated Radio Imaging and Magnetic Field Measurements of the Sun

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As our closest star, the Sun provides an important laboratory to study the processes that govern stars in our Galaxy. The Sun is also the primary driver for the space weather that impacts human life on Earth. The Sun emits electromagnetic radiation from radio to X-ray wavelengths. This proposal will support both the science and operations of a dedicated solar facility the Expanded Owens Valley Solar Array (EOVSA) that will observe the Sun at radio wavelengths. The EOVSA will provide a valuable resource to the solar physics community making important contributions to the science of the solar atmosphere, the 3-dimensional (3D) structure of solar active regions, and the drivers of space weather. The proposal will also support the education and training of the next generation of solar scientists with the involvement of students on levels ranging from high school to graduate students to postdoctoral researchers. This proposal will support the science and operations of the Expanded Owens Valley Solar Array (EOVSA) as a community facility. EOVSA is a solar-dedicated radio interferometer array, located at Owens Valley Radio Observatory (OVRO), in Owens Valley, CA. The science that will be accomplished with the facility includes: (1) locating the acceleration site in solar flares, elucidating the acceleration mechanism(s) for high-energy electrons, and understanding the initiation and evolution of the electron energy distribution; (2) determining the magnetic field strength, direction, temperature, and density as a function of height in the solar atmosphere, including routine mapping of the coronal magnetic field up to several times per day, in order to understand the 3D structure of the solar atmosphere and the initiation mechanisms of solar activity; (3) obtaining daily full-disk images of the F10.7 brightness temperature and eruptive events in order to study the physical mechanisms of magnetically and radiatively dominated processes that impact the Earth and near-Earth space environment; (4) detecting, cataloging, and studying the spectral and temporal evolution of radio flares from flare stars and other nighttime transient sources.