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Federico D'Isa - Master Thesis at IPP Garching

Master Thesis at the Institute for Plasma Physics in Garching, Germany
Reported by Federico D'Isa. Powered by FuseNet.

My name is Federico Antonio D'Isa, I am 24 years old and I am a physics student at the University of Milano-Bicocca in Italy.

The challenge of extreme paricle and heat fluxes

Roughly a year ago, I attended the 2015 edition of the IPP Summer Universty about plasma physics and fusion research, which took place at the Max-Planck Institut für Plasmaphysik (IPP) in Garching near München. This event sparked my interest in thermonuclear fusion and scrape-off layer physics in particular, because the extreme particle and heat fluxes to the plasma facing components (PFC's) are one of the main unresolved issues in fusion research. After the summer school, I decided that I wanted to do my master thesis on a fusion related topic and, thanks to the financial support provided by FuseNet, I was able to do my thesis at IPP.

Density shoulder formation: simulation and experiments

The title of my thesis is "Evolution of the scrape-off layer plasma background at density shoulder formation" and it deals with the formation of so-called density shoulders, i.e. strong transitions in the density profile, that have been observed during several experiments. The formation of these density shoulders occur when filaments - coherent structures that transport plasma across the magnetic field lines in the scrape-off layer - undergo a transition to a certain regime in which transport is enhanced. My work focussed on two different ASDEX Upgrade discharges during which different degrees of shoulder formation were observed.

Several simulations were performed to model the convective transport related to these situations as perpendicular transport coefficients. The results of these simulations were compared to experimental data obtained through Lithium beam, Thompson scattering, Langmuir probe and manometer measurements in terms of the key plasma parameters. The agreement between the experimental and numerical results was evaluated at the midplane, X-point and divertor targets, leading to a more complete picture of the physics involved during the formation of these density shoulder.

An instructive and satisfying experience

During my master thesis, learned how to use really powerful simulation tools such as EMC3-EIRENE code, which allowed me to simulate plasma discharges in a 3D grid, while taking the PFC's into account. Furthermore, the comparison between simulation and experimental data, gave me the opportunity to learn the basic principles of a number of main plasma diagnostics that are being used at ASDEX Upgrade, such as Lithium beam, Thomson scattering, Langmuir probes, CXRS and manometers. Last but not least, my thesis has also helped me to improve my English and to learn how to tackle the problems that are related to frontline scientific research.

My time in Germany has been a very satisfying experience, from a personal point of view, but also for my carreer. My work was very exciting and I got the opportunity to experience life and culture in a different European country, while meeting lots of people from all over Europe. Finally, I would like to thank my supervisors, Daniel Carralero and Tilmann Lunt, for their guidence during my work at IPP.