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Home > Seminars & Defenses > Past seminars, PhD & HDR defenses > 2021 > Séminaires 2021 > Le jeudi 7 octobre 2021 à 10h30

Le jeudi 7 octobre 2021 à 10h30

LPP Laboratory Seminar: Guillaume AULANIER, asstronom at LPP-Observatoire de Paris will give a talk "Building a standard model for solar flares in 3D"

Abstract:

Solar eruptions are the most energetic phenomena of our Solar System. From the free energy contained in the magnetic fields of the Sun’s corona, a single eruption can convert in less than an hour up to several tens of yottajoules into energetic particles and plasma heating, leading to light emission over the whole spectrum -known as the solar flare- and into the bulk acceleration of a large-scale magnetized plasma cloud into the heliosphere -known as the coronal mass ejection.

These natural-plasma phenomena constitute the most intense perturbations of the heliosphere in general, and of Earth’s space environment in particular. Understanding their origins and propagation is therefore a major issue for the development of space weather. It is also a formidable challenge for fundamental astro- and plasma physics. Indeed, eruptions couple nonlinear and multi-scale, ideal and resistive, magnetically-dominated MHD processes. So their understanding requires a tight coupling between state-of-the-art models and dedicated observations.

A standard model for these events has been gradually developped in two dimensions since the late sixties. It now allows to describe most of the components of solar eruptions, but in a phenomenological way for the most part. In addition, many three-dimensional cartoons and simulations have been developped since the late nineties. However, the so-called standard model remains rather incomplete to date. Indeed, the physical mechanisms that are sufficient to trigger and drive eruption remain strongly debated. And also, a comprehensive three-dimensional physical picture accounting for and explaining all the observed features is still lacking.

For the last twelve years or so, the new solar team of LPP has been addressing this topic, which as of today remains one of the key questions of solar physics, and which therefore spans the scientific goals of most modern solar instrumental projects. In this seminar I will present some of the results from this decennial project, with a focus on those involving numerical simulations with our in-house OHM code, and with analyses of space observations from NASA’s Solar Dynamics Observatory.


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CNRS Ecole Polytechnique Sorbonne Université Université Paris-Saclay Observatoire de Paris
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