What is the topic of your PhD thesis?
The overall task is to fully understand the response of a magnetically confined plasma to externally applied magnetic perturbations, which are used to control the occurrence of so-called edge localized modes (ELMs). These disruptive instabilities occur in certain operational regimes in present-day tokamak experiments and are expected to occur in future devices, like ITER. Since they are characterized by intolerable transient heat loads to plasma facing components, it is mandatory to get a grip on them.
Though, the understanding of the topic increases steadily, a complete and thorough understanding of the mechanisms is lacking. So, we investigate the effects of magnetic perturbations on plasmas by applying the kinetic code KiLCA to data from experiments. Furthermore, as part of my PhD project, the code will be upgraded by modifying the underlying model, which treats finite Larmor radius effects by a linear differential operator, to one with a corresponding full integral operator.
Since any approximation is accompanied by missing physical features or even altering certain properties, we expect that improving the existing one will help our theoretical understanding of the control of ELMs by magnetic perturbations.
What is the focus of research?
As mentioned before, the focus is on understanding the processes that happen when magnetic perturbations are applied to a tokamak plasma. In that, it is also important to understand what impact plasma parameters, for example density and temperature, have. Since some parameters are depending, to a certain point, on the configuration of the device, a comprehension of their impact on the control mechanism is necessary to optimize the design of future experiments and, ultimately, fusion power plants.
What is the benefit for fusion research?
When talking about the control of these modes, a full suppression of them seems to be desirable, but that is not necessarily the case. Merely mitigating these instabilities has advantages that could be exploited for the operation of prospective tokamaks. One characteristic is, that they lead to a transport of particles away from the core plasma. This property could be used, to clear the core plasma of impurities. To really arrive at the desired effect though, a deep understanding of the physics behind it is vital.
Additionally, my PhD project is also a step towards the greater goal of our group, namely the modelling of the equilibrium state of a tokamak by means of kinetic theory. This can then be used to extrapolate the physics of fusion devices to different sizes and plasma parameters, leading eventually to the optimization of power plant designs.
What are the biggest challenges?
I did my master’s degree in a different area of physics. So, a personal challenge is to equip myself with a level of knowledge that allows me to conduct research in the area of plasma physics as efficiently as possible, while at the same time already working towards the objective of my PhD project. But, with small and steady steps even the biggest mountain is manageable.
Concerning the project, one specific thing that makes me wary, is the inevitable measurement error that carries on through the whole process and which is difficult to keep track of. Hence, it is important to add an additional layer of skepticism, when thinking about the interpretation of the results.
What plans do you have for your future? What will you be doing in five years? Would you like to continue research or are you going to work in the industry?
Right now, I am focused on contributing to the realization of the technology of fusion energy. In five years, I will most likely have finished my PhD. Other than that, I do not have any fixed plans. But, if the right opportunity emerges, I am certainly not reluctant to pursue a career in research.
What was your motivation to write a fusion relevant PhD thesis? What fascinates you about nuclear fusion?
I am fascinated by the fact that the natural constants in our universe are perfectly suited to carry out the process of nuclear fusion. And that even at a rate, that enables the development of biological life forms on a tiny rock, floating around a giant ball of plasma.
Let alone the need for nuclear fusion, so that heavier elements than hydrogen or helium exist. Otherwise, we would not even have the tiny rock we call home.
Due to the climate crisis, it is inevitable to access clean ways of energy. Renewables provide such a way, but without a sophisticated form of energy storage, they are not ideal when dealing with varying demand or environmental conditions. That’s why a sort of basic supply is necessary. This is where fusion energy will play a major role in the future. This is also my main motivation. I am eager to help combating the probably biggest problem humankind has ever faced.
Moreover, realizing fusion technology is probably one of the most challenging tasks humankind has ever devoted itself to. It is thrilling to be part of such an endeavor, and I am convinced that human ingenuity can bring “the power of the stars” to earth in the next few decades.