[Astronomy seminar] Astronomy seminar on Friday 27th of October

[Astronomy seminar announcements]

Title: Combining observations and 3D numerical simulations for solar 
flare modelling
Speaker: Miho Janvier (Institut d'Astrophysique Spatiale, Paris)

Friday 27th of October from 10:30 to 11:30 at FC61.

Abstract:
Solar flares are the most energetic events taking place in our solar 
system. They result from the conversion of magnetic energy stored in the 
Sun’s atmosphere into energetic particles, heat, and in some cases into 
the launch of solar storms (or Coronal Mass Ejections - CMEs) in 
interplanetary space. Solar flares and CMEs are at the origin of space 
weather events: on Earth, they lead to geomagnetic storms and can be 
responsible for disruptions of satellite systems, as well as electricity 
transport on large-scale national power grids. Auroras, atmospheric ion 
losses, and other effects of space weather also take place on other 
planets in the solar system. Therefore, understanding the underlying 
mechanisms of solar flares is of primary importance to better predict 
their evolution and influence on nearby planets.

Increased temporal and spatial resolutions of ground and space 
observatories have allowed us to refine a standard model for eruptive 
flares, which can explain their generic features (the presence of flare 
ribbons, flare loops and a twisted erupting magnetic structure). In 
particular, 3D MHD modelling has provided us with some predictions on 
the magnetic field behaviour during the eruption, such as the evolution 
of regions where the magnetic field energy is converted. These 
predictions are nowadays well documented with the help of observations 
with, e.g., the AIA and HMI instruments aboard the NASA mission Solar 
Dynamics Observatory.

We will look at how these predictions can be validated with a careful 
study of the active region configuration with different techniques, 
whether with dynamic (MHD) or static (also known as magnetic field 
extrapolations) numerical models. This will show how approaches 
combining different modelling techniques and observations provide a 
major step in extending and completing the standard model for eruptive 
flares in its 3D version.
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