I recently acquired my BSc in physics and am planning to continue my studies on the MSc (and hopefully PhD) level. I have reasonable expectations to get into a very good program dealing on the topics of mathematical and theoretical physics. The main topics covered by the courses in that program are: Quantum Mechanics, QFT and Gauge Theories, General Relativity and Differential Geometry, Stringtheory and Geometry, Statistical Physics and Stochastics. Looking at the people in the program and the research they are conducting, one can see a strong focus on string theory and topics surrounding QFT. The topics taught there do interest me a lot (some research groups focus on quantum computing, which I find extremely interesting), but in regards to my future option I do have a question: In my undergrad studies we have not tapped into plasma physics or whatever I am to understand about it. By plasma physics I am mainly thinking fusion. How do plasma physics and particle and mathematical physics relate to each other? Is the process of fusion understood well enough to now only focus on the application? How does more fundamental research come into play? Is it reasonable to assume that research in particle physics might contribute in some way to fusion research?