Insights into the solar spicule forest from simulations and laboratory experiments

Piyali Chatterjee

Hosted by Indian Institute of Astrophysics (IIA), India on November 3, 2022


Spicular jets are highly elongated chromospheric plasma features that are believed to transport momentum to the solar wind and non-thermal energy to heat the atmosphere. At any given time, it is estimated that about 3 million spicules are present on the Sun. We find an intriguing parallel between the simulated spicular forest in a solar-like atmosphere and the numerous jets of polymeric fluid in the laboratory when both are subjected to harmonic forcing. In our radiative (both 2D and 3D) MHD simulations with sub-surface convection, the solar surface oscillations are excited similarly to those harmonic vibrations. A forest of spicules are formed in our simulations with heights ranging between 6 and 25 Mm, bearing substantially closer resemblance to clusters of jets observed in the solar atmosphere. Taken together, the numerical simulations of the Sun and the laboratory fluid dynamics experiments provide insights into the mechanism underlying the ubiquity of jets. The insight provided by the polymeric fluid experiments when combined with the commonalities with the numerical solar MHD simulations is that four basic ingredients are sufficient to assemble a forest of spicules on the Sun by non-linear wave development.

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