Collaboration with experimental research institutes
The Joint European Torus, JET
JET is the largest experimental fusion device in the world. It is jointly operated by the European fusion associations and funded by EU/EURATOM. Several group members participate in the JET programme, in particular during plasma operational periods, and several researchers are seconded for extended periods up to a few years. JET has been successfully operated up to conditions relevant in reactors, including operation with deuterium-tritium, providing a scientific basis for ITER and future fusion power plant. In 2009-10, the carbon-based plasma-facing components inside the vacuum vessel were replaced by beryllium and tungsten to mitigate tritium retention. Our primary contributions are in developing, maintaining and validation computational models for interpretation and extrapolation of experiments. Several group members utilise JET to obtain experimental data to validate computer simulations. For example, the ASCOT and EDGE2D/EIRENE codes are used to calculate the wall loads due to both fast and thermal particles to understand images like the one given below.
ASDEX Upgrade
The ASDEX Upgrade tokamak is a large fusion device in Garching, Germany, run by the Max-Planck-Institut for Plasmaphysics. Despite somewhat smaller than JET, the tokamak has unique heating systems providing large amounts of non-inductive heating and thus reaching reactor relevant power density. Its plasma-facing components are entirely made of tungsten to establish high-performance plasmas in a device with reactor-relevant materials. ASDEX Upgrade comprised an excellent diagnostic system making is suitable for validation of plasma computer simulations. The Fusion and Plasma Physics group works in close collaboration with the ASDEX Upgrade team in fast particle and edge physics. For example, we have been using one of the edge spectrometer systems to measure the plasma flow in the scrape-off layer for input to and validation of the SOLPS and ERO codes (see figure below). Members of the Fusion and Plasma Physics group frequently visit ASDEX Upgrade for up to four weeks at a time.
DIII-D
The DIII-D tokamak is a largest fusion device in the US, located in San Diego, California, and operated by General Atomics under contract of the US Department of Energgy, Office of Science. Like ASDEX Upgrade, DIII-D comprised an excellent diagnostic system making is suitable for validation of plasma computer simulations. The Fusion and Plasma Physics group works in close collaboration with the DIII-D team in edge physics. For example, we have been using one of the Extreme Ultraviolet divertor spectrometers to measure emission of deuterium atoms and molecules for validation of EDGE2D-EIRENE and UEDGE simulations (see figure below). Members of the Fusion and Plasma Physics group frequently visit DIII-D for up extended periods of time; one of the group's PhD students is visiting DIII-D on a Fulbright grant in 2019-20.
Ioffe Institute, St. Petersburg, Russia
The Ioffe institute is a research institute in St. Petersburg hosting several experimental plasma physics devices, such as the FT2 tokamak. Advanced diagnostics, in particular for plasma fluctuations, allow direct comparison and validation of simulations with the ELMFIRE code. The collaboration includes annual meetings between the groups as well as research visits for extended periods.
ITER
ITER is the first tokamak to be built to reach burning-plasma conditions relevant to future fusion reactors. It is the primary focus of the world-wide fusion effort in magnetic confinement system, jointly carried out by seven international partners. The device is currently (in 2013) under construction at the CEA site in Cadarache, southern France, and expected to be completed by the beginning of the 2020s. First deuterium-tritium plasmas are anticipated by the mid-2020s.
Because of the significance of ITER, the Fusion and Plasma Physics group has strong interest in this project: students from our group are expected to be ITER operators and researchers. Our recent contributions include studies of the effect of the magnetic field homogeneity on fast alpha particles and their power loads to the wall. The studies showed that introducing ferromagnetic inserts can mitigate the peak heat loads due to MeV alpha particles by three orders (see figure below). Other studies include evaluation of the effect of RF and NBI generated fast ions on the measurement capabilities of ITER diagnostics, core transport and MHD stability, and plasma-wall interaction. Several of the group members collaborate with ITER via the various groups within theInternational Tokamak Physics Activity (ITPA).
