Physics projects for Y3 and Y4 students

Twisting a magnetic tube: filament eruption and coronal mass ejections

(supervisor: Xing Li)

Nature of project: data analysis, software

Available to students on full-time physics degree schemes only.

Project description and methodology

How are filament eruptions and coronal mass ejections generated? Some people believe that magnetic reconnections play an essential role in these eruptions. Others believe that the twisting of magnetic flux tubes can lead to filament eruptions and coronal mass ejections while magnetic reconnetions only play a minor role in the erupting procecesses or not needed at all. The twisting of such flux tubes are possible since coronal magnetic field is anchored in the photosphere where the magnetic field is controlled by the turbulent motions of the photosphere. The goals of this project are: 1. to anyalyse Extreme Ultra-violet data (images and videoes) of Solar Dynamic Observatory and whitelight data from LASCO coronagraph;

2. to look for the evidence of twisting of magnetic tubes in filament eruptions and coronal mass ejections;

3. and to evaluate how much twisting is needed to excite filament eruptions.

A successful project will develop beyond the above in one/some of the following directions:
Critical review of MHD kink and torus instabilities

When considering where to take your project, please bear in mind the time available. It is preferable to do fewer things well than to try many and not get conclusive results on any of them. However, sometimes it is useful to have a couple of strands of investigation in parallel to work on in case delays occur.

Additional scope or challenge if taken as a Year-4 project: At the 4th year level, a review of the theory of kink and torus instabilities are needed.

Please speak to Xing Li (xxl) if you consider doing this project.

Initial literature for students:

1. Xue, Z. et al, Nature Communications, Observing the release of twist by magnetic reconnection in a solar filament eruption, | 7:11837 | DOI: 10.1038, 2016
2. Liu, Y., Astrophysical Journal, Magnetic Field Overlying Solar Eruption Regions and Kink and Torus Instabilities, 679: L151–L154, 2008
3. P. Demoulin and G. Aulanier, Astrophysical Journal, CRITERIA FOR FLUX ROPE ERUPTION: NON-EQUILIBRIUM VERSUS TORUS INSTABILITY, 718:1388–1399, 2010.
4. Kliem, B.; Török, T., Physical Review Letters, 96, 255002 – Published 26 June 2006

Novelty, degree of difficulty and amount of assistance required

project was run before. The result was fine.

Project milestones and deliverables (including timescale)