Constraining Solar Coronal Magnetic Fields with New Radio Observing Techniques

Abstract:

Solar radio emission, produced by energetic electrons in the low-beta solar corona, is highly dependent on coronal magnetic field strength and direction, hence offering a rich potential for constraining coronal magnetic fields. However, the observed radio intensity is contributed by several different emission mechanisms and moreover, is known to be sensitive to parameters other than the magnetic field, such as the electron distribution function. Collectively, they introduce ambiguities that are difficult to resolve in the absence of high-quality, broadband radio dynamic imaging spectroscopic observations with sufficiently high spatial, spectral, and temporal resolution. Such observations have not been possible until very recently, thanks to the newly developed radio instruments such as the Karl G. Jansky Very Large Array (VLA) and the Expanded Owens Valley Solar Array (EOVSA). In this talk, we will present first results obtained from the Jansky VLA demonstrating their ability of constraining the coronal magnetic fields in active regions. We will also introduce a forward-modeling tool currently under development, which can be used to reconstruct the 3D coronal magnetic fields based on the newly available radio observations.