Large spatial and velocity space gradients of the energetic particle distributions in fusion plasmas can destabilize a large number of different plasma waves. After reaching a critical amplitude, these waves start to affect the distribution that destabilized them. These non-linear processes often lead to the appearance of transient plasma waves and associated transient transport events. Experimental characterization of such phenomena is difficult due to the rapidly changing parameters of the plasma wave. We have a long history of developing custom-made data analysis methods for such studies mostly based on continuous linear time-frequency transforms.
Task of the doctoral student will be first to get acquaint with the existing methods to characterize the linear properties and quadratic non-linear interactions of these waves, and apply them in an ongoing international effort to understand the complex interaction of different plasma waves and the fast ion population coupled by different resonances. This constitutes dedicated experiments at the ASDEX Upgrade tokamak and synthetic diagnostic modelling on sophisticated wave-particle interaction codes. The final aim is to contribute to improved predictive models of alpha-particle heating for ITER and future fusion experiments. This might have direct conclusions regarding the practical applicability of different magnetical confinement fusion concepts.
Reference: P Zs Poloskei, G Papp, G I Pokol, Ph W Lauber, X Wang, L Horvath: Bicoherence analysis of fast ion driven transient plasma waves, 44th European Physical Society Conference on Plasma Physics. 2017. http://ocs.ciemat.es/EPS2017PAP/pdf/P5.179.pdf
The work is to be carried out in an international collaboration with a lot of travelling. Good command of English language, good basic knowledge in programming, data processing and uncertainty estimation is required.