[English]

Streamer waves

(supervisor: Xing Li)

Nature of project: data analysis, data analysis

Available to full-time physicists only.

Project description and methodology

Streamers are large structures which can be seen above the solar limb when using a coronagraph. They are very bright compared to the background corona. Streamers are often the source regions of coronal mass ejections. It is widely believed that a long current sheet exists at the central region of a streamer. Normally quite stable, large scale waves along streamers can be occasionally seen when strong eruptions (coronal mass ejections) occur near such streamers. In this project, data from LASCO C2 and C3 telescopes onboard SOHO satellite will be used to investigate waves propagating along streamers or very thin structures in the field of view of C2 and C3. C2 and C3 white light images will be used to find the period, wavelength and propagation speed of streamer waves. It is then possible to derive the magnetic field strength and the dependence of magnetic field strength on the distance to the center of the sun.

A successful project will develop beyond the above in one/some of the following directions:
Critically review MHD wave theories (how MHD waves develop/behave along coronal structures).

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: Use image processing/enhancing techniques to better display wave patterns.

Initial literature for students:

  1. Chen, Y., Song, H.Q., et al., Astrophysical Journal, 714, 644, 2010.
  2. Nakariakov VM, Verwichte E. 2005. Coronal Waves and Oscillations. Living Reviews in Solar Physics 2
  3. Roberts B, Nakariakov VM. 2003. Theory of MHD waves in the solar corona. Presented at Turbulence, Waves and Instabilities in the Solar Plasma, Dordrecht, Netherlands; Boston, U.S.A.

Novelty, degree of difficulty and amount of assistance required

The project was previously run with very good results.

Project milestones and deliverables (including timescale)

milestoneto be completed by
Choose/familiarize a software package (IDL/solarsoft or other) to handle LASCO data.end of October
Survey LASCO online data for streamer wavesChristmas
Find streamer wave properties (wavelength, period, and phase speed)end of February
Analyse the magnetic field along streamers as a function as heightEaster