Speaker
Description
The Sun is a vast laboratory of plasma. In solar corona, the plasma rests in the heterogeneous magnetic field networks, which are rooted in the photosphere. Besides, solar plasma in corona is also dynamic, which is most drastically seen during a solar flare. Overall, solar emission is inherently variable in space and time. The MWA solar observations have captured this variability and produced most detailed solar maps at meter wavelengths at a fine time cadence. Here, I will present the results from two pieces of work from MWA solar data.
I. At meter wavelengths, coronal propagation effects like scattering and refraction are quite significant and significantly alter the observed brightness distribution of the solar emission. However, these effects have remained hard to quantify. I will present a quantitative comparison of the perceived brightness distribution in the MWA solar maps with simulated thermal bremsstrahlung at corresponding frequencies. We find that the scattering extensively re-distributes the brightness within the solar disk. To give rise to this observed behaviour, coronal density inhomogeneities 1%-5% are required.
II. MWA solar observations have demonstrated the presence of a large population of the energetically-weak releases associated with an active region. Motivated by this, we perform a near-simultaneous study of a gyro-synchrotron (GS) radio source using L-band of VLA and MWA. This source was highly variable, long-lasting and was associated with a complex active region. I will discuss the results from the source modelling and the energy released by such long-term GS sources.
| Suggested presentation duration (minutes) | 20 |
|---|
