Design and Implementation of a Multi-Element Solar Radio Interferometer at 1.42 GHz

Abstract Solar flares and Coronal Mass Ejections (CMEs) are two examples of solar explosive and transient phenomena. Both phenomena give rise to characteristic signals in the radio band in decametric and hectometric ranges, with more associated phenomena such as Type III and IV radio bursts. Additionally, in the Quiet Sun emission, we can observe radio signatures in these ranges, coming from the low Corona. In this article we describe the design process, validation in simulation, implementation and results of a multi-element radio interferometer for solar observations at 1.42 GHz. The development of the instrument was divided in two phases. An initial phase with the design of a 2-element drift interferometer, where each of the antenna elements is a $2\times 2$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>2</mml:mn> <mml:mo>×</mml:mo> <mml:mn>2</mml:mn> </mml:math> printed Yagi-Uda element array with an eight meter baseline. For the second phase, a 4-element radio interferometer was designed. For each element we use the same printed Yagi-Uda antennas in the focus of a parabolic reflector dish, and a fully-steerable pier. The signals correlation are performed electronically using a R econfigurable O pen A rchitecture C omputer H ardware ( ROACH ) unit, with a downconversion stage for each element, and the pipeline for data acquisition, processing and visualization is done entirely on Python. We also show the obtained results for testing in each phase, as well as the First Light of the full interferometer.