For studies of the solar atmosphere, microwave observations possess a unique sensitivity to magnetic fields which frequently dominate the energetics of the active solar corona. For studies of the flaring atmosphere, the shape and parameterization of the spatially resolved microwave spectrum provide a powerful diagnostic both of the ambient magnetic fields as well as of the electron temperature, density and spectrum. This program of solar microwave spectroscopy is funded in order to exploit this sensitivity for the study of solar flares and the magnetic structure of active regions during the peak of activity in the current solar cycle. The work will be based primarily on observations from the frequency-agile interferometer at the Owens Valley Radio Observatory, which provides high spatial resolution observations at up to 86 frequencies from 1 to 18 GHz. This unique instrument is currently being upgraded so that its combination of imaging and spectroscopy to more complex sources. The studies conducted under this grant will benefit from and contribute to other facets of the MAX'91 program which include soft and hard x-ray and gamma ray imaging as well as other ground-based and balloon observations.//
