Description

Flowing out from the Sun is a continuous stream of material known as the solar wind. The solar wind transports mass and energy away from the Sun and is also the background through which solar eruptions (coronal mass ejections, CMEs) propagate on their way towards us.

The solar wind is a combination of fluid-like plasma and magnetic field. It turns out that the solar wind and CMEs can be approximated to a reasonably good accuracy with purely fluid-like motion, with the magnetic field just "along for the ride". And further, the fluid motion is predominantly radially outwards from the Sun allowing the use of simplified 1D or 2D models.

Solar wind speed in the 1D numerical model of Owens et al. 2020. Note how the Sun's rotation creates a spiral outflow (think spinning spirkler).

This project will start by reviewing a classic model for the solar wind known as Parker's model to give some intuition about the system. After this we will review some different approaches to modelling the solar wind and CMEs and dig deeper depending on your interest. One potential project from this point would be to reproduce the results of Owens et al. 2020 and write a 1D python solver for Burgers' equation (this will build on what you learn in the Fluid Mechancs III and PDEs courses). Where you could look into different solving methods and test cases for your code, and then try out some different evolving boundary conditions (e.g. the "cone" CME model, which is just a big velocity pulse). Another would be to look into different "kinematic" CME models, where a simple magnetic field representing a CME is evolved by a specified flow (e.g Owens et al. 2006).

Prerequisites

Fluid Mechanics III is essential to be taken alongside this project. PDEs III would also be useful (but not essential). Part of the project will likely involve building your own Python code to solve some sort of initial value problem, so some confidence with python coding would be useful.

Resources

In addition to the papers linked above, there are many general reviews of the solar wind that could be useful for context (e.g. Viall & Borovsky 2020). There are also lots of resources for solving Burgers' equation in python, e.g. this tutorial.