Culham Plasma Physics Summer School: Day 8, 9 and 10

Hello! You poor soul, you've made it through the whole of this awfully long blog!

On the morning of Day 8 we saw the return of Dr Thyagaraja, or Chippy, for a lecture on Plasma Transport. This was a follow-on from his earlier lecture on the more basic Classical Transport, and, well, the maths was a little more advanced too - to say the least. After celebrating with my girlfriend the night before, this lecture was a bit of a struggle! But I persevered!
Next up was a lecture on Plasma Turbulence, given by UK Atomic Energy Authority CEO Prof. Steve Cowley. This was another very interesting lecture that didn't dwell too much on complicated maths, but focused much more on understanding key concepts - something my hangover and I really appreciated
The final lecture of the day was on Plasma Wall Interactions given by Dr Fulvio Militello. This wasn't so much on the appreciable engineering problem that is to create sufficiently resilient materials to withstand the hostile conditions inside future tokamaks (i.e. ITER, DEMO), but was focused more towards the effect these interactions have on the stability of the plasma itself. This wasn't something that I had thought about at all, and I found it very interesting. I found myself really looking forward to Dr Militello's next lecture the following morning!

But first came the tour of MAST! I was particularly excited for this because I had not been shown around MAST on my previous visit - so this was all new. It was also very interesting because MAST is currently undergoing an upgrade, so I got to get up and close to the vacuum vessel itself! Here's a picture I managed to snap:

MAST
And that about wraps up Day 8.

The highlights of Day 9 were certainly the first two lectures. It started off with another lecture from Dr Militello, but this time titled Edge Physics of Tokamak Plasmas. This was a very interesting lecture on the rich physics at the edge and the scrape of layer (SOL). This, together with the lecture on instabilities, have made me want to do much further reading into these fields. I can see myself continuing to do research in these areas.
Next up was a lecture on Dusty Plasmas from Dr Michael Coppins at Imperial. At first I didn't expect this lecture to be very interesting at all, but it turns out Dr Coppins is a world-leading expert in this field - and boy, was I wrong! A dusty plasma is a plasma that has millimeter to nanometer-sized particles suspended in it. The reason that dusty plasmas are interesting is that the presence of these additional particles alters the charged particle equilibrium leading to different phenomena. Electrostatic coupling between these particles can vary over a wide range, leading to weakly coupled (gaseous - more similar to what we're used to) to strongly-coupled crystalline plasmas. For example, below is an experiment done in zero-gravity onboard the International Space Station (ISS):
Example of self-organisation in crystalline plasmas
Dusty plasmas are interesting because they provide a non-Hamiltonian (i.e. irreversible) system of particles as a means of studying the fundamental physics of self-organisation, pattern formation, phase transitions, and scaling (e.g. could this be used to study webs of dark matter?).

After another two lectures, we sadly came to the end of our penultimate day at Culham. However, we were in store for a treat - the Banquet at St Edmund's Hall!

I was lucky enough to sit across from Professor Roger Cashmore, Chairman of the UK Atomic Energy Authority (the man who introduced the summer school). Here's a screenshot of the highlights of his career from the 'Key Staff' page on CCFE's website:
So as I'm sure you can imagine - he had a few interesting stories to tell! Of course, it was lovely to have a final meal with my peers too. We all exchanged stories over good food and wine.
After the banquet, we had a few drinks in the Hall bar. I was lucky enough to have a chat with Prof. Steve Cowley, CEO of the UK Atomic Energy Authority. Let's hope it helps me secure a future PhD placement with him!
When the Hall bar closed, we moved on to another bar (I honestly don't remember where it was or what it was called), and on the way we got this picture!

Now for the last day... :(

We had a lecture from Dr Stuart Mangles on Laser Wakefield Acceleration, which is a proposed method of accelerating particles using the wake from an electric plasma wave. See the figure below to get an idea for the physics:
Source: Wikipedia
The principle was first demonstrated experimentally in 1988, but the field has recently seen many advancements and is looking very promising! 

Finally, we had a very interesting lecture from Dr Jakob Svensson on Connecting Theory with Experiment. This was essentially a deep look at a more 'philosophical' understanding of Bayesian statistics - something which is often overlooked. I really enjoyed the approach of this lecture. Dr Svensson's first slide was this:

The point being that in science we often try to infer quite a lot of detail just from some numbers of some screens. How exactly do we do this?
In general the forward problem is quite an easy one to solve, i.e. measuring the temperature of some conducting wire. The inverse problem is far more difficult to solve, and is often the one that we are most interested in - going from data to understanding the underlying physics. Dr Svensson explained it like this:


And the rest of the lecture followed in a similar style - nothing too complicated, but he raised some important 'philosophical' points that really made me think. This all ties in very well with a course I'm taking next term called Statistical Data Analysis - so I'm hoping to learn more about Bayesian probability theory there. All in all, this was a great way to finish the course.

After the final lecture, we all got the coach back to Oxford train station and from there people went their separate ways! We all promised to keep in contact with each other - and maybe one day we'll even be working with each other!

So a big thanks to the Culham Plasma Physics Summer School - everyone who taught, organised and attended it. I had an excellent time. And a big thanks to The Ogden Trust for funding me on this trip.