On July 1st I arrived in UK to stay in Abingdon-on-Thames, a nice little town nearby Oxford, during an unusually hot summer. Thanks to the FuseNet support, I spent two months there doing an internship at JET Facilities, UKAEA (UK Atomic Energy Authority) Culham Science Centre, for my Master thesis in Plasma Physics. It was a great opportunity to stay in an important research centre, to meet people working on fusion topics, and to see in person JET (Joint European Torus), which is the world’s largest and most powerful tokamak.

Isotope effect on transport

My thesis work is a study of isotope effect on particle and energy transport through simulations and analysis of some JET shots. Investigating transport changes associated with main ion species changes is a fundamental topic in the view of deuterium-tritium plasmas in ITER. Experiments have been made on JET to compare plasmas in hydrogen and deuterium. Since the experimentally observed behaviour of energy confinement with isotope mass is opposite to basic theoretical expectations, detailed modelling of these plasmas is required to examine the possible causes of the observed breaking of the expected scaling. Several mechanisms have been identified and each needs to be evaluated in the specific conditions of the JET experiments. This may be done by employing quasi-linear transport models, such as TGLF (Trapped Gyro-Landau-Fluid)model, or giro-kinetic models, such as GENE. I used TGLF implemented in ASTRA transport solver to simulate some ofthe JET L-mode shots with ILW (ITER Like Wall) in deuterium or in hydrogen with different values of NBI and ICRH power. I could study stiffness and ion heat fluxes calculated by TGLF and compare them with GENE known results for H and D plasmas.

Beyond the work

In these months I met many interesting and kind people at JET Facilities; it is a wonderful environment where you may work and learn. There are also extra activities for all tastes like dance lessons, BBQ festival, tennis, and musical fair. I enjoyed very much taking part to a tour of RACE, a facility of UKAEA where they are conducting many activities in the field of Robotics and Autonomous Systems. Its main aim is developing remotely operated solutions to run and maintain a fusion reactor, but there are a lot more work in adjacent fields such as smart infrastructure, intelligent mobility, and driverless vehicles!

- Irene Casaraghi