Abstract Details
| Name: Divya Oberoi Affiliation: NCRA-TIFR Conference ID: ASI2018_798 Title : Solar radio astronomy at low radio frequencies: The dawn of a new era Authors and Co-Authors : Atul Mohan (NCRA-TIFR), Surajit Mondal (NCRA-TIFR), Rohit Sharma (NCRA-TIFR), Akshay Suresh (Cornell University), Leonid Benkevitch (MIT-Haystack Observatory), Iver Cairns (Sydney University), Kamen Kozarev (Bulgarian Academy of Sciences), Colin Lonsdale (MIT Haystack Observatory), Patrick McCauley (Sydney University), John Morgan (Curtin University) Abstract Type : Contributed Talk Abstract Category : Sun and the Solar System Abstract : The low radio frequency Sun is much more dynamic than what is observed at higher frequencies. The bulk of this dynamics comes from short-lived narrow-band features arising from non-thermal emission processes. Interestingly, such features are often also seen even during periods of low solar activity. As opposed to emissions at other wavelengths, which are thermal in nature, emissions at these frequencies arise from coherent plasma emission mechanisms. As a consequence, these emissions form a very effective probe of processes involving much lower levels of energy. This is vindicated by the fact that these emissions tend not to have counterparts at higher wavelengths like EUV or X-rays. While these advantages of low-radio frequency observations have been appreciated for a while, their application has been comparatively limited. The most important reason for this has been that tracking the rapid changes in solar emission across time, frequency and morphology required a spectroscopic snapshot imaging capability over a wide band, which, till recently, was beyond the available instrumentation. Riding on the wave of the enormous progress in digital technology, a new class of radio interferometers, much better suited for the needs of solar imaging, have become available comparatively recently. The Murchison Widefield Array (MWA) is one such instrument. It is located in the very radio quiet Western Australia, operates in the 80-300 MHz band and is one of the two precursors to the Square Kilometre Array. With its ability to provide high dynamic range and high fidelity solar images with good time and frequency resolutions across a bandwidth which can be distributed across the entire instrumental band, the MWA provides an exciting opportunity to realise the promise of solar radio physics. Here we briefly describe the recent progress which has been made in using the observations from the MWA, including development of the necessary tools and studies of the weak non-thermal solar emissions. We will also discuss our short and medium term science objectives, spanning applications ranging from investigations of coronal heating to exploring ways of assessing geo-effectiveness of Coronal Mass Ejections. The availability of instruments like the MWA mark the dawn of a new era in using the capability of solar radio observations to address a diverse set of interesting and outstanding problems in solar physics. |