Dear All,
We have the pleasure of announcing the next instalment of the UK-SOSS, which will take at 10:00 am (GMT) on 10th March 2022. Our speaker is Prof Andrew Hillier from University of Exeter.
We look forward to welcoming you all to the talk at that time.
With warmest regards,
Jiajia, Marianna and Chris
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Speaker: Prof Andrew Hillier (University of Exeter)
Title: Partially ionised plasma dynamics in the solar atmosphere
Zoom link:
Meeting ID 953 3817 1418
Abstract:
The lower layers of the solar atmosphere are predominantly filled with neutral atoms with only relatively few charged particles. So, despite magnetic fields being a key driver behind many of the dynamics observed, the majority of the particles do not directly feel the Lorentz force of the magnetic field. Instead, this force is transferred through coupling processes like particle collisions and charge exchange. As all these processes happen on a finite timescale, the coupling between the neutrals and the magnetic field is not perfect. So, for example, for dynamics that can be high frequency (e.g. waves and instabilities), naturally high-frequency dynamics (e.g. shock fronts) or physical process that are fundamentally multi-scale like turbulence or magnetic reconnection, neutrals can undergo vastly different motions to those of the charged species. For these processes, it becomes important to model both the ionised plasma and the neutrals as separate fluids to properly capture the dynamics. In this talk I review recent results from my group from our studies of the role of partial ionisation in MHD dynamics looking at how instabilities, shocks and reconnection change when the charges and neutrals are modelled as separate fluids. I will also provide some thoughts on how these processes may manifest in observed dynamics in the solar atmosphere.