Hello! My name is Agnieszka Bukowicka, and I am a fifth-year Chemical Physics student at the University of Edinburgh, Scotland. As part of my degree, I had an outstanding opportunity to undertake a 9-month-long master's thesis placement at the Max Planck Institute for Plasma Physics in Greifswald, Germany.
My research project at the IPP Greifswald focused on commissioning and evaluating the performance of a test rig for neutral gas pressure gauges (NGPGs) development. These gauges are located inside the plasma vessel, where high magnetic fields above 1 T are present, measuring the neutral gas pressure. This helps to evaluate particle exhaust, which is necessary for efficient plasma fuelling and minimising material erosion and migration due to plasma-wall interaction.
The NGPGs have to face multiple challenges during the nuclear fusion reaction, including high magnetic fields. The usual test facilities for NGPGs involve superconducting magnets requiring cryogenic temperatures or conventional magnets restricted to short pulses of the order of a second. However, these experiments are costly and time-consuming, limiting the development of this diagnostic tool and calling for a new solution: the Halbach test rig.
The test rig consists of a cylindrical Halbach array of permanent magnets with varying polarisation. A Halbach array is a special arrangement of magnets that creates a strong magnetic field on one side while cancelling out the field on the other side. This configuration generates a 1.4 T confined magnetic field inside, with a near-zero net field on the outside. The NGPG inserted into the Halbach cylindrical magnet experiences this high magnetic field, simulating the conditions inside the plasma vessel.
The first challenge of my project was to commission the test rig, which required establishing reliable and stable data acquisition and automating the data storage so the user could monitor the test rig conditions live. This task greatly boosted my confidence and provided me with valuable hands-on experience in Python programming.
The second challenge was to evaluate how long the NGPG can operate inside the magnet. The gauge consists of a cathode that heats up to 1300°C, emitting thermionically electrons—a process where electrons are released from the cathode due to the heat. This process also heats the surroundings, including the magnet, which at high temperatures can lose its magnetic properties. Moreover, the adhesive used between magnetic arrays posed the threat of outgassing and adsorbing on the cathode surface and lowering its emission. To investigate the limits of the magnet, I developed a magnet heating model and used a high-accuracy time-of-flight mass spectrometer. This task was a lot of fun and really showed me how interdisciplinary science could be. I would never have guessed that during my master's placement, I would analyse glue compositions!
Apart from my project, I spent my weekends travelling by train, bike or on foot around Mecklenburg-Vorpommern. Northern Germany has so much to offer in terms of nature—like the Caribbean-looking Rügen cliffs or the beautiful white beaches of Usedom. Moreover, Greifswald is a student town, so there are always social events to enjoy. This year taught me a lot, and every day was a new adventure. If you consider coming to IPP Greifswald, I would absolutely recommend it!
To finish, I would like to thank FuseNet for its generous support, which enabled me to pursue my dream of joining fusion research. I am also deeply thankful to my supervisor who guided me through my placement and became a great source of inspiration. Lastly, I would like to thank my colleagues at IPP Greifswald, who provided me with invaluable support and always greeted me with a smile.
