Online Seminar “Parametric resonance of Alfven waves driven by ionisation-recombination waves in the weakly ionised solar atmosphere”

Star-UBB Seminar Series:- Parametric resonance of Alfven waves driven by ionisation-recombination waves in the weakly ionised solar atmosphere

Parametric coupling of waves is one of the most efficient mechanisms of energy transfer that can lead to the growth or decay of waves. This transfer occurs at frequencies close to their natural frequencies. In partially ionised solar plasma there are a multitude of waves that can undergo this process. In his presentation, the speaker will present results of a recent study on the parametric coupling of Alfven waves propagating in a partially ionised solar plasma with ionisation-recombination waves that appear in a plasma in ionisation non-equilibrium. Depending on the parameters that describe the plasma (density, temperature) the coupling can lead to a parametric resonance. Their study determines the occurrence conditions of parametric resonance, by finding the boundaries between stable and unstable regions in the parameter space. Their results show that collisions and non-equilibrium recombination can both contribute to the onset of unstable behaviour of parametrically resonant Alfven waves.

時間:2024.05.30(四) 16:00~17:30
頻道:Zoom ID:853-7454-4159 ←
講者:Prof. Istvan Ballai (Plasma Dynamics Group, School of Mathematics and Statistics, University of Sheffield, Sheffield, UK)


Scientific and Technological Advanced Research- Babeș-Bolyai University(Star-UBB) Seminar Series in Gravitation, Cosmology and Astrophysics

Presently a period of rapid and intense change are being witnessed in our understanding of the gravitational force, at a rate that is quickly increasing since the important observational discoveries of the late 1990s. With the advent of new observational techniques, the emergence of important cosmological and astrophysical paradigms can be seen that lead to a deep change in our understanding of the Universe. Astronomical observations strongly suggest that at large scales the force of gravity may not behave according to standard general relativity, and that a generalization of the gravitational action, either at the geometric level, or at the matter level, may be required for a full understanding of the gravitational interaction.

The goal of the present seminar is to bring Theoretical Gravitational Physics closer to the observations and experiments, and to discuss current topics in general relativity, high-energy physics, astrophysics and cosmology.


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