Thesis supervisor: Tamás Zoltán Szepesi
belső konzulens: Gergő Pokol
Location of studies (in Hungarian): Centre for Energy Research (EK) Abbreviation of location of studies: BME
Description of the research topic:
An increasing demand for the pellet injection technique is experienced within the fusion community over the 2020s. This demand is driven by the advantages of pellet injection over gas puffing: pellets can deposit their material deeper in the plasma, and the reaction time of a pellet-based actuator can be even an order of magnitude faster. For this reason, pellet injection is not only regarded as the ultimate method for refueling fusion reactors, but recently it is also considered for the injection of radiative impurities. Fusion experiments are gradually approaching reactor-relevant conditions for a few selected parameters such as electron density or magnetic field. Hence, pellet injection experiments are entering unprecedented regimes where simulations are not benchmarked either, and considering the importance of the pellet injection technique for future reactors, the investigation of these new regimes is essential.
The task of the applicant will be to investigate pellet ablation in such new parameter regimes by means of simulations and experiments.
Most experiments will be carried out at Wendelstein 7-X (W7-X), the world’s most advanced superconducting stellarator-type fusion experiment in Greifswald (Germany), but other fusion devices may also be considered. W7-X is equipped with a steady-state capable pellet injector starting operation in 2024, offering a unique possibility for exploring new pellet injection regimes. A fast visible camera system, operated by the video diagnostics team in EK-FPL, is capable of recording pellets with 5-microsecond time resolution, and serves as one of the main diagnostics of pellet-plasma interaction. The task of the applicant includes, on the one hand, on-site experimental work (set-up and operation of fast cameras) and the processing of measured camera data, and on the other hand, developing and running simulations for W7-X pellet injection scenarios in the possible new parameter regimes, and the comparison of the results with pellet injection experiments.
The simulations would be carried out using a well-established code, capable of dealing with 3D geometries and associated secondary effects such as inhomogeneous ablation. Additionally to W7-X, the applicant has to run simulations for COMPASS Upgrade, a small, high-magnetic field (5 T) tokamak, being built in Prague, Czechia. EK-FPL is planning to deliver a pellet injector for this experiment, which would allow the exploration of pellet-plasma interaction at high magnetic fields. The task of the applicant is the optimization of the pellet injection geometry by modelling.
Required language skills: English Further requirements: Good command of English language, programming skills, availability to participate in Wendelstein 7-X fusion experiments for several weeks. Advantage: experience in python coding.
Number of students who can be accepted: 1
Deadline for application: 2024-05-31
2024. IV. 17. ODT ülés Az ODT következő ülésére 2024. június 14-én, pénteken 10.00 órakor kerül sor a Semmelweis Egyetem Szenátusi termében (Bp. Üllői út 26. I. emelet).
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