Next Generation Measurements of the Coronal Magnetic Fields Above Solar Active Regions with the Frequency Agile Solar Radiotelescope

It is well known that microwave emission from the solar corona above active regions contains detailed information on the 3D structure of the magnetic field. Several studies have investigated the details of how to extract this information from the spatially resolved microwave spectrum such as that measured with the Very Large Array (VLA) and the Expanded Owens Valley Solar Array (EOVSA), two radio arrays that can perform such microwave imaging spectroscopy. We use a period of joint observations by these two arrays during the 2017 Aug. 21 solar eclipse to validate a 3D coronal magnetic field and thermal plasma model of a large active region, based on HMI, AIA, and the GX Simulator modeling framework, and then explore what the emission from the model predicts would be seen with the Frequency Agile Solar Radiotelescope (FASR), a next-generation radio facility. Using a realistic antenna configuration for FASR, we show that direct diagnostics with the instrument will allow model-independent measurements of the 3D active region coronal magnetic field strength and direction on short timescales. Such a capability presents a wonderful opportunity to obtain quantitative measurements of active region coronal magnetic field evolution on both short and long timescales, relevant to energy storage, buildup, sudden release, and longer-term decay/dissipation.