Large spatial and velocity space gradients in the energetic particle distributions of fusion plasmas can destabilize a wide range of plasma waves. Having reached a critical amplitude, these waves start to affect the fast particle 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 challenging 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, mainly based on continuous linear time-frequency transforms (https://github.com/fusion-flap/nti_wavelet_tools)
The task of the doctoral student will be first to become acquainted with the existing methods for characterizing 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 electron and ion populations coupled by various resonances. This involves dedicated experiments at the ASDEX-Upgrade, MAST-Upgrade, and JT-60SA tokamaks, as well as synthetic diagnostic modeling on sophisticated wave-particle interaction codes. The ultimate goal is to contribute to the development of improved predictive models for alpha-particle heating and runaway electron mitigation in ITER and future fusion experiments. This might have direct consequences regarding the practical applicability of different magnetic confinement fusion concepts.
The work is to be carried out in an international collaboration, which will involve travel to various fusion devices. A good command of the English language, as well as a solid foundation in programming, data processing, and uncertainty estimation, is required. Experience in fusion plasma physics is an advantage.