The Collaboratory
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Growing up, I never really struggled to choose a career. Regardless, even though I was sure I wanted to pursue physics, it took me a while to understand why, and more specifically, which branch? I remember at my second trimester in uni reading about a new fusion milestone in a scientific dissemination magazine called ‘I f***g love science’ which was all over my Facebook feed. It was one of the classic articles published every so often regarding fusion: ”X’s artificial sun sets new record”. That was the first time I read about the properties of a plasma, and how magnets could be used to confine it. It stuck with me, but I didn’t really understand it until I took my first formal electromagnetic theory lectures. The concepts seemed quite straightforward. A plasma is just a state of matter formed by charged particles. A charged particle generates an electric field. A moving charged particle generates an electric current. An electric current generates a magnetic field. A magnetic field interacts with charged particles. It all seemed like a self-contained loop elegantly explained by Maxwell’s equations. But this picture is incomplete without an understanding of nuclear physics. And honestly, straightforward concepts too. Charged particles exist in equal numbers, making matter neutrally charged since opposite charges attract. And, just like a solid turning into a liquid when heated, the liquid will turn into a gas if you continue applying heat. Eventually, if you heat the gas enough, electrons will have enough energy to separate from atoms, hence creating a “blob” that’s formed by positively and negatively charged particles. That is a plasma, which is the most common state of matter in the universe. Surely enough, you can use magnets to make the charged “blob” move in a way that’s convenient. That’s the challenge?
Well, the challenge is: To create a fusion plasma, you need to heat your matter a lot. That takes energy. However, when two small atoms combine to form a larger one (fuse), energy is released. The game is to get more energy out from these atoms fusing than what you had to put in to persuade them to do so.
Then came the revelation. Well, if moving charged particles generate an electric current, which generates a magnetic field, could you not use that same magnetic field to contain your plasma? At least it would interact with itself, right? Yes and no. It is, of course, never that easy… One of the reasons is that some of the particles remain neutral (without a charge) in the plasma, so how do you confine those?
I had, of course, read about JET and MAST-U. The flagships of fusion. Never did I, in my wildest dreams, imagine I would end up standing by either of them. The first year of my PhD, I saw JET’s outer room with the 9th octant. In the second year, some of my PhD buddies moved to Oxford and had an office from which window you could see the MAST-U hall and all sorts of cool memorabilia, like a central solenoid with the imprint of an ELM (a hot plasma filament burned a line around it). Since then, UKAEA lingered in my mind as a cool possible place to work after my PhD.
The feeling of community and acceptance since I arrived in the UK has been incredible. I truly believe that Fusion is one of the most welcoming communities I’ve ever experienced. This was no different when I had to start looking for a place to conduct a research visit at. One of the coolest (in my humble opinion) perks of the Fusion CDT program is that they push (and pay) for you to go somewhere else to collaborate on a short project. For some, this is exactly what happens; for others, this project provides a big chapter in their thesis, and for a few, this project evolves into their full PhD project. Connections, networking, and even people securing jobs at internationally renowned science institutions are part of the stories I’ve heard from what we call ‘the collaboratory’. Finally, it was my turn.
Don’t let the idea that the collaboratory being a part of the Fusion CDT means that anything is a sure thing, a big part of the experience is creating the research proposal yourself. You have to ask things like: What would a cool place to go be? What could I do there? Are there any places doing research I am really interested in? Some funding is coming from the CDT, but a lot of students opt to ask the receiving institutions for something extra to cover extra time, flights, accomodation, visa, etc. From there, you have to come up with an idea that either is completely different from your research, or if you are on a visa, something that is closely enough related that it can go into your thesis. Planning goes from budgeting and finding accomodation to planning a scientifc project that can be done in ~1 – 3 months (yes, this is an extremely short time to do something complex, which is why people end up with project that take longer), finding a supervisor at the institution you want, etc. Oh! And, as always, we can’t forget the risk assessments.
So it began, the planning of my collaboratory; I had always liked the idea of somehow being part of MIT. One of the most present figures in the YPI is Chris Ridgers, a man famously known for being part of all the projects in the world, or at least a ton of them in fusion, offered to help. He helped me contact people at both MIT and CFS to see if I could collaborate with them. We all seemed excited and happy with what came up. Unfortunately, for reasons that had to do more with politics than physics, the project was binned.
However, all was not lost. From this experience, I got in contact with Mike Kryjak. He was working on a field of research so closely related to mine that one would’ve thought we should’ve met earlier. In a short time, he helped me develop a proposal worthy of being accepted. In the blink of an eye, I found myself in the Culham Center for Fusion Energy, the home of JET, MAST-U, and the forefront of most of Europe’s fusion research, which I had visited all those months ago as a newborn PhD candidate. Mike mentored me for over a month, showed me the ropes of the code we used, and introduced me to the brand names in Culham. Imposter syndrome hits again. Harder. How did I go from being a random Mexican kid who was somewhat good at maths in high school to having lunch with the director of the United Kingdom Atomic Energy Agency, while it’s being discussed if a new divertor design will work? What am I supposed to say? How do I contribute?
Regardless, I tried to become an expert in exhaust region physics throughout the month. I was in too deep to allow them to see their mistake. The idea behind my collaboratory project was to reveal if neutral particles that can move across the magnetic field in the reactor were responsible for the unexpected behavior in density on our simulations, which were seen in both our code (Hermes-3) and the one used at ITER (SOLPS). Seconds, hours, and days spent staring at code. Around Tuesday of the second week, I started to understand the connection between the code, the graphs, and the theory I learned months ago. I could see and understand the problem. The progress meetings became more of a discussion and less of a tutorial. It felt less and less like I was being taught by an older brother how to play a complex video game with his cheat codes on and more like we were all trying to figure out something really hard and potentially new. It is as if everyone in the room had a piece of the puzzle, and the only way to finish it was to describe your piece and how it fits with everyone else’s. I could, for the first time, understand that I was also holding a piece, even if it was a small one. I still remember the first time I asked a question to my supervisor, Peter Hill, and he replied: ‘I don’t know. Probably no one else in the world knows. That’s why you are doing this’. I was terrified. But good things come from this adrenaline-induced fear. And few feelings are as great as finally cracking the problem you have been working on for weeks, and showing it to the few people in the world who understand it.
I started to write this as “A common day in the life of a Fusion PhD student”. A common day? Most days in the life of someone who does fusion are common. At least mine are, and this was no different when I was doing my collaboratory. You get up, cycle, drive, walk or take the bus to work, get a cup of coffee, chat a bit to your office mates, stare at a computer screen for hours, have meetings, get lunch, stare at a computer screen for more hours, have meetings that require you to stare at a computer screen, go home, maybe workout, share dinner with someone if you are lucky. But I don’t think there is anything common about a day in the life of someone who is doing something as extraordinarily remarkable as fusion. You get up, have a breakfast that hopefully will allow you to solve the mysteries of the universe throughout the first half of the day. Then, you cycle, drive, walk, or take the bus to work, and you enjoy it since a fusion reactor 8 light minutes away from Earth is surprisingly visible despite the inclement British weather. You stare at a screen for hours trying to make sense of either a math problem that hasn’t been solved for centuries, trying to understand a theory which most absurd simplification consists of 16 equations that follow 1**22 particles each 1**-8 seconds, trying to decipher the data spat out by machines built to see what happens at the hottest place in the solar system (built by some of the most brilliant minds ever, but still is only a line on the screen), or trying to teach a computer to think and show what would happen inside said hottest place in the solar system if you slightly tweak something. You have meetings trying to decide what the best way to harness a celestial form of energy is, or why the specific bug in your code is preventing you from finding it. You then eat lunch with some of the most remarkable individuals you’ve met, capable of great reasoning, abstraction, and scientific thinking, while discussing which pub you will all attend after 5 pm to forget about all of that. In the end, I believe every common day is extraordinary when you can see the extraordinary in the common.
Article written by and with thanks to Sebastian Ruiz Gonzalez.
Featured picture taken by Sebastian outside of the MAST-U hall.