Temperatures of almost 40 degrees, heavy rain from a hurricane, half a meter of snow, a tornado warning. I have experienced it all during my 3 months internship in Princeton, USA. A big thanks to Fusenet, Marco de Baar [DIFFER, TU/e] and Egemen Kolemen [Princeton University, PPPL], for providing me the opportunity of visiting Princeton University / Princeton Plasma Physics laboratory and to be part of the plasma control group.
The project was about predicting neoclassical tearing modes, certain plasma instabilities, that appear in tokamaks. Especially for large scale tokamaks such as ITER, these instabilities reduce confinement and can cause unacceptable disruptions. Because it is desirable to predict and subsequently prevent these modes, the following research question is formulated: can the onset of NTMs be predicted using offline data from equilibrium solvers by perturbing these equilibria and carry-out a stability analysis? The reasoning motivating this work is that close to the stability boundary, a small perturbation may lead to an unstable plasma topology, which will be reflected in changes in statistical properties of certain stability characteristics. Unfortunately, the results did not allow me to predict the modes. It is likely that this is due to accumulation of error bars and so it is advised, for further research, to perform an adequate error analysis.
Although the results were not very satisfactory, I did learn a lot! Not only about ‘fusion theory’ and ‘computational practicalities’, but also about the country, history and politics. I participated in tours in the United Nations Headquarters in New York, the Pentagon and Capitol in Washington D.C. and the independence hall in Philadelphia. The National Museum of African American History and Culture puts the US in an honest historical perspective, definitely a recommendation. My internship ended with an inspirational trip to top universities Harvard and MIT. Where after I gained personal career advice, from the Director of the Institute for advanced studies, professor Robbert Dijkgraaf, in Einstein’s old office.
- Joost Lammers