High Fidelity Solar and Heliospheric Imaging at Low Radio Frequencies: Progress and Future Prospects

The latest generation of low frequency interferometric arrays is revolutionizing solar and heliospheric imaging capabilities. Via a combination of large numbers of independent antennas and greatly increased computing capacity, sufficient information can now be gathered and processed to generate high fidelity images at high time and frequency resolution. For the first time, it is possible to reconstruct spatially, temporally and spectrally complex solar emissions in detail, to measure interplanetary scintillation for many sources simultaneously over wide fields of view, and to track heliospheric disturbances via rapidly evolving propagation effects. These new and rapidly improving capabilities will help to address a range of long-standing scientific questions in the field. We review the current state of the art of low frequency imaging instruments, with particular emphasis on, and examples from, the Murchison Widefield Array (MWA). The limitations and challenges of such arrays are explored, and the prospects for next-generation ground and space based arrays yielding additional major advances in capability are reviewed.