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Resolving the solar prominence/filament paradox using the magnetic Rayleigh–Taylor instability

By Dr. Jack M. Jenkins & Prof. Dr. Rony Keppens


Lab information

Prof. Dr. Rony Keppens and I are a part of the Center for mathematical Plasma Astrophysics @ KU Leuven’s mathematics department. Currently funded by the ERC Advanced Grant ’PROMINENT’, we are intrigued by the ‘ultimate condensation’ dynamic associated with the formation of solar prominences within the atmosphere of the Sun. This is perhaps more broadly known as the fundamental ‘thermal instability’ process believed to occur throughout astrophysics. In general, we are an active team that collaborates internationally to derive and test plasma theories with direct applications to the Sun and solar wind. This includes a drive to constrain numerical models with, and in turn benchmark, any and all conclusions against, observational studies and derived theories.


Scientific material

Solar prominences are gigantic, cool ten thousand degree plasma arcades that arc several tens of million meters into, and can snake yet ten times further across, the million-degree atmosphere of the Sun. What makes these structures so interesting is the enormous range of scales associated with their existence, be it their lifetimes, internal structuring and dynamics, ambient magnetic field properties, or basic appearance. Since the solar atmosphere adheres to the large-scale, single fluid description of ‘magnetohydrodynamics’ (MHD) we know that the behaviour of these prominences bear resemblance to a menagerie of processes observed throughout the cosmos. The fantastic opportunity that these solar prominences afford us is our ability to observe them up close and at fantastic both spatial and temporal resolution. Nevertheless, there are many physical conclusions that remain out of reach of observational studies alone, and so we are turning increasingly to numerical models to help bridge these gaps in our knowledge. Herein, the aforementioned broad range of associated scales succeeds in setting the stage for this to be a challenging numerical endeavor.


Figure 1: Synthetic synthesis of the simulation domain to appear as observational quantities routinely taken of the solar atmosphere. The upper row describes the synthesis for the solar filament phenomenon, with the lower row presents the synthesis for the solar prominence phenomenon.


In order to maximize the confidence in any results that we obtain, we need first to ensure that our models of solar prominences are as physically accurate and detailed as possible. To achieve this, we have made use of the open-source MPI-AMRVAC toolkit to solve the set of nonideal MHD equations, including a complete consideration of the involved physics. Furthermore, the leading computing resources available at the Vlaams Supercomputer Centrum have enabled us to achieve a stable simulation resolution of approximately 7003 cells, with an effective resolution of a staggering 20 thousand meters, exceeding that of state-of-the-art observations, over a 24×24×30 million meter domains. Finally, the accurate conversion of the primitive variables within the simulations to those recorded by routine observations of the solar environment ensures a robust validation of our models. Most excitingly, the extreme resolutions afforded by the VSC systems open, for the first time, a predictive capacity for what modern instrumentation onboard upcoming facilities (Solar Orbiter, the Daniel K. Inouye Solar Telescope) will find.

The VSC already has a strong history of contributing to our understanding of this topic. It has now enabled us to confirm the historical invocation of the magnetic Rayleigh-Taylor plasma instability with respect to solar prominences, and simultaneously extend a challenge to observational astronomers to provide comparable observations. Jack M. Jenkins | KU Leuven

The results of the latest study that resolves the longstanding solar prominence/filament paradox are featured in Nature Astronomy. Herein, we demonstrated the 1-1 correspondence between our models and observations and went on to generalize our understanding of the self-consistent generation of vertical structuring within the prominence projection. The VSC already has a strong history of contributing to our understanding of this topic. It has now enabled us to confirm the historical invocation of the magnetic Rayleigh-Taylor plasma instability with respect to solar prominences, and simultaneously, extend a challenge to observational astronomers to provide comparable observations.


Read the full research article on the Nature Astronomy website

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