The Expanded Owens Valley Solar Array (EOVSA) is a radio interferometer dedicated to the study of the Sun located at the Owens Valley Radio Observatory (OVRO). It collects microwave imaging spectropolarimetry measurements of the Sun and space weather phenomena in the microwave frequency band. The proposers seek to operate EOVSA as a community resource, making the data public to all users within hours of collection. The chief science aims of the array are the study of solar flares, the magnetic and plasma structure of solar active regions, and drivers of space weather. EOVSA provides a test bed for prototyping of antennas, feeds, analog and digital systems, calibration methods, and data management for the Frequency Agile Solar Radio Telescope (FASR), a proposed next-generation solar radio observatory.
The proposers will operate the Expanded Owens Valley Solar Array, which uses radio interferometry to collect full-disk images of the Sun every second in a series of wavebands in the frequency range of 1-18 GHz, excluding 1.9-2.4 GHz due to noise. The instantaneous bandwidth is 500 MHz; it switches between each band in 20 ms, allowing full coverage of the whole frequency range in 1 second. The data they collect will be used to study solar flares, solar active regions, and sources for space weather. EOVSA consists of 13 2.1-meter radio dishes, with a 27-m dish used for high-sensitivity calibration. The array covers an area 1.1 by 1.2 kilometers in extent, and operates seven days a week, from sunrise to sunset. The proposers seek to use the Array as a community instrument, not only making the data available to the larger solar astronomy and space weather community, but also using the system a testbed for prototyping systems for potential future instrumentation in the microwave.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
