• Promotor: Prof. Kristel Crombé
  • Mentors: Luis Daniel Lopez Rodriguez, Johan Buermans, Arthur Adriaens
  • Study programs: Master of Science in Engineering Physics, Master of Science in Physics and Astronomy, Master of Science in Teaching in Science and Technology (Physics and Astronomy), European Master of Science in Nuclear Fusion and Engineering Physics
  • Location: Research Centre Juelich (Germany), Royal Military Academy (Brussels), at home

Problem setting

Are you fascinated by plasma physics and its role in controlled nuclear fusion? Would you like to gain hands-on experience with cutting-edge diagnostics in a real experimental environment? This thesis offers an exciting opportunity to work on TOMAS (TOroidal MAgnetized System), a unique testbed for wall conditioning and plasma characterization located at the Forschungszentrum Jülich (https://www.fz-juelich.de/) in Germany.

Plasma-surface interactions (PSIs) are critical in fusion devices like ITER and Wendelstein 7-X (W7-X), where materials at the reactor walls undergo modifications due to plasma exposure. These interactions can affect plasma purity and overall reactor performance. To mitigate these effects, various wall conditioning techniques—such as plasma-assisted deposition, glow discharge cleaning (GDC), and ion/electron cyclotron plasmas—are being explored. TOMAS is a flexible, hands-on environment where students can directly contribute to understanding and optimizing these techniques.

Technical details of the machine are and earlier results are described in [Goriaev21] and [Rodriguez24]. 

[Goriaev21] : A. Goriaev et al., "The upgraded TOMAS device: A toroidal plasma facility for wall conditioning, plasma production, and plasma–surface interaction studies," Rev. Sci. Instrum., 92, 023506 (2021), https://doi.org/10.1063/5.0033229 

[Rodriguez24] : D. López-Rodríguez, "Characterization of plasma parameters and neutral particles in microwave and radio frequency discharges in the Toroidal Magnetized System," Rev. Sci. Instrum. 95, 083542 (2024), https://doi.org/10.1063/5.0219487

The TOMAS device

Outside view of the TOMAS machine with various diagnostics.

Inside view of TOMAS

Inside view of TOMAS during plasma operation, showing the Langmuir probe to measure plasma parameters.

Objectives

This master thesis project involves characterising different plasmas in TOMAS using a range of advanced diagnostics. The beauty of this topic is that multiple students can work on it simultaneously, each analysing the plasma from a different perspective, making this a truly synergistic and collaborative research experience.

Available diagnostics and techniques:

  • Quadruple Langmuir Probe (QLP): Measures plasma density and temperature profiles.
  • Retarding Field Energy Analyzer (RFEA): Determines ion energy distribution functions.
  • Time-of-Flight Neutral Particle Analyzer: Provides insight into plasma-neutral interactions.
  • Camera-based 2D Density Imaging: Visualizes plasma structure in real-time.
  • Microwave Interferometer: Measures line-integrated density variations.

The goal of this thesis is to build a complete picture of plasma behaviour under different experimental conditions, including:

  • Plasma types: Glow discharge, electron cyclotron (EC), and ion cyclotron (IC) plasmas.
  • Operating parameters: Gas species (He, H, D), power levels, neutral pressures, magnetic field strengths.
  • Wave injection effects: Influence of wave orientation on plasma characteristics.

Key tasks:

Experimental Work: Conduct plasma measurements using state-of-the-art diagnostics.
Data Analysis: Compare plasma density and temperature across different species and conditions.
Modelling & Collaboration: Work with theorists and wave propagation specialists to interpret results.

Your work will directly contribute to optimizing plasma-wall interactions and will be highly relevant for future fusion reactors like ITER!

Ideal for students passionate about plasma physics and fusion energy, experimental research and diagnostics, hands-on laboratory work and data analysis. 

Location

The main location will be the Forschungszentrum in Jülich (close to Aachen, Germany), where the experimental device TOMAS is situated. The student should be prepared to spend a couple of weeks (spread out over the academic year) in Jülich for the preparation and execution of the experiments. Data analysis can be done from home. Discussions with the promotor and supervisor can happen in Ghent, Brussels (Royal Military Academy) or Jülich, as desired.