### Theory of magnetic reconnection

#### (supervisor: Youra Taroyan)

Nature of project: **theory**, software

Available to
students on full-time physics degree schemes or joint students.

#### Project description and methodology

Magnetic reconnection produces some of the most fascinating plasma processes we can observe in the universe. Reconnection can occur in a slowly changing quasi-steady state, which may contribute to coronal heating, but more often happens as a sudden violent process that is manifested as flares and coronal mass ejections.

The project will review the theory of magnetic reconnection with a focus on 2D reconnection. Basic concepts in magnetic reconnection such as magnetic diffusion, evolution of a stagnation point flow and current sheets will be discussed.

*A successful project will develop beyond the above in one/some of the following directions:*

The balance between a stagnation point flow and magnetic diffusion will be explored analytically for one dimensional inflows and for two dimensional incompressible flows using illustrative examples (Priest 2014, Chapter 6).

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:* The balance between a stagnation point flow and magnetic diffusion will be explored analytically for two dimensional compressible flows.

Please speak to **Youra Taroyan** if you consider doing this project.

*Initial literature for students:*

- Priest, E. Magnetohydrodynamics of the Sun, 2014, Cambridge University Press
- Aschwanden, M., Physics of the solar corona, Springer 2005
- Stix, M. The Sun, Springer 2002

#### Novelty, degree of difficulty and amount of assistance required

The project is suitable for students interested in analytical work.

#### Project milestones and deliverables (including timescale)

milestone | to be completed by |

Understanding of the main concepts in reconnection theory | end of October |

Theoretical Review and preliminary analytical results | Christmas |

Derivation of the solutions for example problems | mid-March |

Discussion of results | Easter |