A new perspective on particle acceleration on the Sun: Solar flare radio observations with the Karl G. Jansky Very Large Array

Solar eruptive events, in particular solar flares and the often associated coronal mass ejections allow us to study fundamental processes in magnetized plasmas such as magnetic energy release, particle acceleration, and particle transport. These are ubiquitous in the Universe and at the core of many plasma physics applications. At the same time, solar eruptions are the drivers of space weather. As such they are responsible for occasional disruptions of technical systems on the ground and are a potential danger to human space activities. With this project we will study the fundamental processes of particle acceleration and transport in solar flares using unprecedented radio observations from the Karl G. Jansky Very Large Array (VLA) in combination with multi-wavelength context observations from solar space-borne observatories. With the VLA we have, for the first time, the means to make images at superior spectral resolution and make spatially resolved spectra of flare-related radio emission. This presents a unique opportunity to explore a new field of research from its beginning.During the three-year duration of this project, the first two years will be dedicated to studying electron acceleration in flare-related jets and their significance for the solar wind. Since solar flares are very heterogeneous and complex, this will be done both as case-by-case study of specially selected events and, subsequently, as a larger statistical study over many events. During year three, we will work toward understanding the primary acceleration region and acceleration mechanism by studying radio bursts from within the acceleration region. The proposed work will make use of already existing, but not yet analyzed, VLA observations of solar flares. Additionally, starting in the first year of the project I will also plan and apply for additional observing time with the VLA with the goal of having observations approved and scheduled in year three to guarantee continuity beyond the current project.Due to the novel and largely unexplored nature of solar VLA observations, the proposed work is expected to make major contributions to our current understanding of particle acceleration and transport in solar flares and how they affect space weather, and to also stimulate fundamental plasma physics research. As a result it will lay the foundations for a strong and continued involvement of the Swiss Heliophysics community in radio observations of solar eruptions, in particular in view of and in preparation for upcoming missions such as ESA’s Solar Orbiter (launch in 2018), and it will establish FHNW as a key player in the growing field of solar radio imaging spectroscopy.