Profile

Fusion happens when atoms collide and stick together, releasing a lot of energy in the process. This is going on in the Sun and other stars all the time, but we’re trying to harness the energy to make a power station here on earth.

Fusion could be a great power source because:

1. There are no carbon emissions

2. We have huge supplies of the fuel (types of hydrogen) which should last for millions of years.

3. One kilogram of fusion fuel can provide the same amount of energy as 10 million kilograms of fossil fuel.

4. No long-lived radioactive waste.

5. It is very safe. A large nuclear accident is not possible.

6. It would be reliable and could be turned up or down to meet demand (unlike most renewable energy).

For the fuel we use 2 types of hydrogen called deuterium and tritium. To get them to collide we have to give them lots of energy by heating them up to about 100 million degrees (which is why fusion is difficult to do!). When we heat the fuel to this temperature it changes from a gas to something called a plasma, which can be trapped by magnetic fields. We trap it in a machine called a tokamak, a Russian word for a ring-shaped magnetic chamber (the diagram below shows 2 tokamaks that have been cut in half).

I work on MAST (the Mega-Amp Spherical Tokamak), a squashed version of a normal tokamak, which is at the Culham Centre for Fusion Energy near Oxford. Here’s a video of plasma in MAST. Culham also has JET, the largest tokamak in the world (the big shiny machine below! … the pink glow is the plasma).

I study structures called magnetic islands which can appear in a hot tokamak plasma. Magnetic islands can cause heat to leak out of the plasma and reduce the amount of fusion, so we want to avoid them. My work is to study measurements of magnetic islands growing inside MAST to help to understand why they grow so we can stop this happening in the future. The graph below shows how hot it gets in MAST – but the magnetic island causes a step in the temperature and causes heat to leak out.

At the moment, fusion uses more energy than it produces … but only just! The next step is ITER, a really big tokamak that is being built in the South of France. It should produce 10 times more energy than it consumes and prove that fusion is possible. ITER will be switched on in about 2018 … so it’s a really exciting time to be involved in fusion research. If you work hard you could be there to see it happen!

I work in a big office at the York Plasma Institute at the University of York with other PhD students who also study plasmas – mostly for fusion but also for other things like medical applications or simulating big plasma explosions in outer space. We all have lots of work to do but we do find a bit of time for tea, cake and watching funny youtube videos.

I spend most days writing computer code to do maths and statistics on data from the tokamak. We can measure lots of different properties of the plasma like the temperature, the magnetic field, the speed of plasma flow and the density of particles and they all tell us how close we are to getting fusion to work. Here’s a map of the temperature around a magnetic island (see ‘More about me and my work’ section for a description of magnetic islands). Red is hot and green is cold – can you see the island shape? The temperature has a constant value inside the island.

Last year I worked at the Culham Centre for Fusion Energy (near Oxford) for 3 months. While I was there I got to run some experiments on MAST. Those days were not typical at all. We made the plasma really hot so that a magnetic island grew, then cooled it down again to make the island go away. By looking at how they appear and disappear, we can understand how to avoid them in future. Running experiments was sometimes frustrating because you can’t always make the plasma do what you want, but overall it was really fun and a bit insane to think how hot we were making the plasma (10 million degrees!).

I’ve had quite a few other non-typical days. I’ve been to 2 conferences to present my research – one on the coast of Scotland and one in Salt Lake City, USA. I also cycled from York to a plasma physics summer school in the Netherlands (about 125 miles each way). Summer schools and conferences are a great part of being a scientist – you get to travel to exciting places, meet other people from around the world working on the same subject as you and then go and then go to the pub with them.

Here’s a picture of me cycling through the Netherlands .. they have awesome cycle lanes so getting hit by a car is really unlikely.

Here’s a panoramic view of Salt Lake City taken on my phone.

When I’m not doing physics I like making music on my computer, going on massive bike rides, watching obscure films and eating interesting food.