“The Distortion of Radio Observations by the Heliosphere”
Dr. Nicolina Chrysaphi
Laboratory of Plasma Physics, Sorbonne University
Thursday 20 June 2024, 15h CET
The Full Seminar Talk Available Here
Abstract:
Radio photons can interact with heliospheric density fluctuations that influence their observed properties, whether the photons have solar or extra-solar origins. I will demonstrate the importance of accounting for
such interactions, with particular focus on scattering which is the dominant radio-wave propagation effect. By combining observations of solar radio bursts and simulations, we showed that scattering is anisotropic and that ignoring its effects can be detrimental to any inferences made from observations. Such anisotropy also induces a dependence of radio measurements on the observer’s angular position, including on the observed size, position, and flux. However, we recently employed an improved fitting method and analysed multi-vantage observations from four angularly-separated spacecraft, identifying the decay and rise times as the only radio burst measurements which are independent of the observer’s position. We also identify scattering effects as an important contributor to the rise phase of the solar radio light curves we record, adding to our understanding of the plasma emission mechanism.