Non-thermal Parametric Studies in the Quiet-Sun of the Transition Region
The transfer of mass and energy taking place through the transition region is generally determined by the filling factors. Dere et al. (1987) reported the filling factor to be ranging from 10^-5 to 10^-2 using C IV line. The corresponding path lengths were found to be in the range of 0.1 - 10 km. However, we use density-sensitive lines like O IV and S IV to estimate the electron densities and temperature using high-resolution spectral observations binned to 2” in spatial resolution from the Interface Region Imaging Spectrograph (IRIS). We also devise using new atomic models for the quiet Sun, which include density effects, photo-ionisation, and charge transfer to estimate the path lengths and filling factors. We also conduct studies of centre-to-limb variation of non-thermal velocities. The parametric studies will be useful for interpretation of observations from Solar Orbiter SPICE spectrometer and future TR modelling.
Dr. Yamini K. Rao is a Postdoctoral Fellow at the Department of Applied Mathematics and Theoretical Physics, University of Cambridge, currently working on non-thermal energy studies in the chromosphere and transition region of the Sun. She is also a Fellow of Royal Astronomical Society. Yamini uses spectroscopic and imaging observations from ground and space-based telescopes to probe the flows and energy from lower atmosphere to the upper atmosphere of the Sun. Her research interests are EUV spectroscopy, flows and energy in the TR, etc. She completed her PhD in 2020 from Indian Institute of Technology, Varanasi, in India, before moving to Cambridge. Her thesis topic was “Plasma Flows and their physical implications in the Solar atmosphere.”