Developing nuclear fusion power would create a zero-CO2, safe and continuous energy source with no long-lived radioactive waste. This is highly desirable for society, but a great challenge is to control the waste heat which arrives in the exhaust region, known as the divertor. This must be reduced to manageable levels before it reaches the wall, so that the reactor operates reliably over long timescales. Recent developments have opened a new path to power exhaust: to use a liquid metal (lithium) based wall which strongly evaporates, forming a vapour cloud in front of the wall which cools and redirects the heat, ultimately preventing any damage.

To achieve this requires the prevention of excess vapour from reaching the core of the plasma, which would reduce the power output. This can be achieved by dividing the divertor into a series of differentially pumped chambers allowing re-condensation of the vapour on the wall surfaces, known as a Vapour Box Divertor. The goal of the PhD is to investigate and validate the potential of this solution, with the aim to prepare future testing in a fusion device.

The Plasma Material Interactions group
The PMI group works to solve the challenges of power exhaust for ITER and for future fusion reactors, and also applies its expertise in extreme plasma conditions for industrial problems and novel materials processing. Our main foci are on

1. Understanding the expected performance of the ITER divertor using Magnum-PSI
2. Exploring new approaches for heat exhaust in fusion reactors, such as liquid metal walls
3. Understanding the impact of impurities on the performance of mirrors in Extreme Ultraviolet plasma sources

Responsibilities and tasks
The research will be carried out using DIFFER's experimental facility Magnum-PSI, which is a globally unique linear plasma device, the only one in the world capable of producing reactor relevant heat and particle fluxes, and therefore the perfect tool to explore this approach. You will:

• Develop hypotheses and experiments to study the physics mechanisms responsible the vapour cloud shielding.
• Design and test a prototype Vapour Box Divertor and use these results to validate modelling predictions.
• Identify the optimum operational conditions to promote differential pumping and recirculation of the recondensed vapour.
• Produce and publish scientific publications and present your work at national and international conferences.
• Produce and defend a doctoral thesis at the Eindhoven University of Technology.

• You have (or very soon will have) a recent Master's degree in science and technology of nuclear fusion, physics, engineering or materials science.
• You are able to work well both independently and as part of a team in an experimental setting.
• You can produce outstanding academic results and can work with originality and high scientific quality.
• Prior experience in one or more of nuclear fusion, plasma physics, atomic physics, spectroscopy and bolometry will be considered a plus but not an essential requirement.
• You have excellent English language proficiency.

DIFFER is the Dutch Institute for Fundamental Energy Research, one of the nine research institutes of the Netherlands Organization for Scientific Research (NWO). In our institute we focus on a multidisciplinary approach to energy research, combining physics, chemistry, engineering and materials science. DIFFER's research takes place in two main themes: Solar Fuels for the conversion and storage of renewable energy and Fusion Energy as a clean and unlimited source of energy. At DIFFER we develop and support a national network on fundamental energy research and collaborate closely with the academic community and industrial partners.

Our institute offers a first class and international research environment with various interdisciplinary but related research topics and projects. When fulfilling a PhD position at DIFFER, you will have an employee status as junior scientist at NWO. You can participate in all the employee benefits NWO offers. NWO and DIFFER have number of regulations that support employees in finding a good work-life balance. Such as conditions for teleworking, partly paid parental leave, the possibility to purchase and sell holiday leave, and a mentoring program. You will get a contract for four years. Your salary will be up to a maximum of 3,007 euro gross per month. The salary is supplemented with a holiday allowance of 8 percent and an
end-of-year bonus of 8.33 percent. A training program is part of the agreement: you and your supervisor will design a plan for the additional education and supervising that you specifically need, for example through several courses offered by NWO (see https://www.nwoi.nl/en/personnel/information-for-phd-students-and-postdocs/special-courses-for-traineeresearchers).
The doctoral degree will be awarded by the Eindhoven University of Technology (TU/e, www.tue.nl). General information on working at NWO can also be found at the NWOI website (www.nwo-i.nl).