If you need more information on any proposal, send an e-mail to the corresponding contact person.
If you want to apply for one of those topics, please follow the procedure indicated on this page .
- Study and optimization of electron density profiles, turbulence characteristics and instabilities in the edge and pedestal of TCV plasma
Observations  point to the fact that over all tokamak plasma particle and energy confinement is dominated by transport properties in the plasma edge. At the same time in the so called H-mode regime of plasma confinement, the edge confinement pedestal is very often unstable and there are frequent, large expulsions of plasma particles and energy into the surrounding volume depositing a significant fraction of the plasma particles and energy onto the plasma facing components with the potential to damage these components. The expulsions are referred to as Edge Localised Modes (ELMs). It is planned to operate ITER in the H-mode confinement regime and it is likely that ITER will suffer ELMs. One avenue of current tokamak physics research is to understand the physics of ELMs and explore avenues to quench the ELMs and/or to mitigate their effects. High spatial and temporal resolution measurements of electron density profiles and electron density turbulence in the plasma edge will help elucidate the central role of the plasma edge in tokamak confinement and lead to a better understanding of ELM physics and inter-ELM confinement. A particular goal would be to develop a viable type-II ELM regime, in which target heat loads are significantly reduced while the confinement remains good. As in other tokamaks, this regime is achieved at TCV with high plasma triangularity and high density. We are seeking one or two motivated PhD students to pursue these topics. Part of the work would include further development of a prototype, extremely high resolution, millimeter-wave pulsed reflectometer  and Doppler backscattering (DBS)  system for the characterisation of edge density profiles, turbulence characteristics and poloidal flow velocity in the plasma edge in both standard confinement, or L-mode, and H-mode regimes. An additional system to feature prominently, particularly in the study of H-mode and ELMs, is the Phase Contrast Imaging diagnostic which measures density fluctuations. It is expected that a significant effort be placed in enhancing the existing hardware and optimising its use. Interaction with the groups from the experimental department as a whole will be necessary and collaboration with the SPC theory group is expected.
 O. Sauter et al, Phys. Plasmas 21, 055906 (2014)  P. Molina-Cabrera et al, to be submitted to Rev. Sci. Instrum.  P. Molina-Cabrera et al, Rev. Sci. Instrum. 89, 083503 (2018)
- Fast-ion deuterium alpha (FIDA) Spectroscopy
Contact person:Dr. MER B.P. Duval
Neutral heating beams are often used in thermonuclear devices to heat the plasma above that achievable by passing large currents through the plasma resistance (Ohmic Heating). The fast neutral atoms injected are well above thermal (called fast-ions) and must slow down in the plasma to efficiently heat the thermal plasma. FIDA spectroscopy takes the light emitted from the interaction of the fast ions/atoms within the plasma to analyse the spatial and velocity profiles of these ions from injection to thermalisation. These fast ions can be taken as a proxy for the fast Helium atoms created by particle fusion (the basic process of energy production concerned) and as they slow, they are subject to many interactions with the target plasma that can prematurely eject these fast ions, which could be catastrophic as their energy is used to keep the plasma hot and thus reactive. TCV has recently installed such a fast ion heating beam and preliminary FIDA spectroscopy shows a rich range of physical processes. This thesis will commence with the installation of two multi-chord spectroscopic systems to observe FIDA light. Many experimental probes on the effect of plasma shape and other parameters (density, temperature etc.) will follow. The student will use the FIDASIM program developed by a worldwide group to interpret the spectra together with detailed plasma transport modelling to diagnose the fast ion behaviour. This work will be part of a new and developing group at the SPC looking into fast ion behaviour on the TCV Tokamak.
- Isotope effects for H-mode confinement regime in TCV
Contact person: Dr. B. Labit
During the Pre-Fusion Power Operation Phase (PFPO), ITER will operate in the so-called H-mode regime of good confinement with Hydrogen and/or Helium as the main ion species. Nevertheless, most of the existing scaling used to quantify H-mode efficiency are based on Deuterium plasmas and therefore the extrapolation to Hydrogen or Helium plasma is largely uncertain. From H or He plasmas, compared to D plasmas, the goal of this thesis is to advance the understanding of crucial issues associated with the H-mode physics among which the L-H transition, the confinement with dominant electron heating, the fueling efficiency, the pedestal transport, the first wall and divertor heat loads, etc. The candidate will design and conduct experiments on the TCV device, the tokamak at the EPFL. New analysis tools together with theoretical models will be implemented.
- Development of an imaging neutral particle analyser (I-NPA) for TCV
Contact persons: Duccio Testa, Basil Duval, Alexander Karpushov
TCV is now equipped with a high power (1MW) / high-energy (25keV) Neutral Beam Injection (NBI) system, with a second system being planned to deliver fast neutrals at even higher energy (50keV). The injected fast neutrals then ionize in the plasma, producing supra-thermal ions which, in turns, may undergo charge-exchange neutralization and be expelled from the plasma. These ejected fast neutrals can be measured using a neutral particle analyzers and can then be used as a proxy to determine the fast ion distribution function in some relevant phase-space region.
TCV is currently equipped with a compact NPA, and major improvements will be needed to measure the fast ions produced by the second NBI system, hence the development of a new I-NPA, currently at the stage of conceptual design. This thesis will commence with the completion of the design, procurement, installation and commissioning of the I-NPA system, and will then move onto the analysis of the measurements obtained with this system, and other fast ion diagnostics, towards the development of a multi-diagnostic tomographic reconstruction of the fast ion distribution function. This work will be part of a new and developing group at the SPC looking into fast ion behavior on TCV.
- Thomson scattering data analysis for real-time applications
Contact person: Dr. P. Blanchard
On the TCV tokamak, reliable electron temperature and density profiles are routinely obtained from Thomson Scattering (TS) measurements. In 2013-2014, the TS diagnostic has undergone a substantial upgrade which is opening the road to real-time (RT) applications of such parameters.
In the frame of a PhD, algorithms for RT analysis of TS signals should be first developed and tested along with the implementation of a new DAQ system. The availability of electron temperature and density profiles in RT could then be used for TCV scenario development and actuator control like microwave heating system as well as inputs for RT transport code like RAPTOR.
Real Time Control of Tokamaks
Contact person: Dr Federico Felici
The SPC tokamak TCV is equipped with an advanced real-time control system, based on matlab-simulink and which allows rapid and flexible developments. In addition, we have developed a rapid tokamak transport simulator, RAPTOR, capable of simulating in real-time current density and kinetic profiles. This is a perfect environment for PhD thesis project related to real-time control of tokamaks, including magnetic control, plasma profile control, as well as advanced topics such as scenario control, monitoring and supervision.
Measurement of turbulence and modes driven by and interacting with the high-energy NBI ions in TCV
Contact person: Dr. Duccio Testa
Analysis of NBI-driven magnetic turbulence and modes in TCV, and interaction of MHD instabilities with the slowing-down NBI ions; develop and test mathematical tools for the magnetic turbulence analysis as needed; develop high-frequency magnetic sensors based on LTCC technology.
Contact person: Prof. Ivo Furno
Understanding the interaction of plasma turbulence with suprathermal ions, i.e. ions with energies greater than the quasi-Maxwellian background plasma, is a major challenge for the next generation of magnetic fusion reactors. While experimentally challenging in fusion devices, suprathermal ion measurements are accessible in basic devices with extended diagnostic capabilities and flexible configurations, such as the TORPEX device at SPC.
We are seeking for a Ph.D. candidate to conduct detailed investigations of basic aspects of suprathermal ion-turbulence interaction on TORPEX using a controllable suprathermal ion source and diagnostics, which allow fully time-resolved 3D measurements of the suprathermal ion dynamics. In parallel with the experiments, the Candidate will use state-of-the-art numerical codes to obtain 3D simulations, which will be compared with experimental data and theory predictions. The proposed subject is of fundamental importance for nuclear fusion and crosses the frontier between plasma physics and research in complex systems.
Contact person: Dr. Duccio Testa
Analysis of the Toroidal Alfven Eigenmode (TAE) measurements obtained in JET using the upgraded TAE system, including real-time control applications, MHD spectroscopy, and in preparation of studies of alpha-driven TAEs during the DT experiment planned at JET for 2017-2018.
Note: the upgraded TAE system should become operational around the end of 2014 or early 2015.
Overall data analysis for JET also to include comparison with all fast ion diagnostics and other turbulence diagnostic.
Contact person: Prof L. Villard
The SPC theory group has been active since many years in the field of numerical simulation of magnetized fusion-relevant plasmas by developing codes that are run on some of the currently most powerful High Performance Computing (HPC) platforms. In particular, the realistic description of low frequency turbulence from first principles using gyrokinetic theory, which remains a great simulation challenge, has been one of the group’s main research focus. The loss of heat and particles associated to this turbulence is a key limiting factor in achieving the conditions required in a fusion reactor. The architecture of the most powerful HPC platforms has been evolving towards more heterogenous systems (CPU+GPU or CPU+MIC) and there is therefore the need to adapt our physics application codes to this new type of machines. We are currently looking for a PhD candidate that is seriously motivated to deal with advanced numerical simulations of gyrokinetic turbulence and actively engage in the current effort to adapt our codes to the new generation platforms. The thesis will thus include both physical studies as well as technical aspects. The successful candidate will interact with our group at SPC and other institutions and laboratories.
Contact person: Kamil Sedlak
The Swiss Plasma Center (SPC) of Ecole polytechnique fédérale de Lausanne (EPFL) is looking for a Ph.D. student to work on the R&D for low-temperature superconducting cables to be used in future generation fusion reactors (tokamaks).
Our superconductivity group of SPC is involved in design, development and test of high current / high field superconductors for large fusion magnets, including the ITER conductors. The tests are performed in the unique SULTAN test facility at SPC Villigen. In the scope of the EUROfusion DEMO conceptual design activity, we are developing a novel Nb3Sn conductor/magnet, based on the so-called react-and-wind technique, which will allow a drastic improvement of the effectiveness, i.e. a cost and space reduction for the DEMO magnets.
The project, supported by the Swiss National Fund, aims at understanding the performance degradation of the brittle Nb3Sn in large cables. A key aspect is the discrimination between reversible and irreversible degradation, by correlating the actual strain state of Nb3Sn with the performance evolution. A large data base is available at SPC from a decade of ITER and prototype conductor testing. New samples are also prepared with advanced instrumentation. The Ph.D. candidate will face the challenge of identifying the mechanisms of degradation through experiments (e.g. in-situ Tc measurements on large cables) and analysis (strain distribution function from Tc data). The candidate may also propose and apply new methods. The ultimate goal is to master the strain and control the degradation in the Nb3Sn conductor design and magnet operation.
The candidate is expected to address also other aspects of the DEMO magnets that will be identified during her/his research work, e.g. cooling, mechanical loading, handling and manufacturing issues. Candidates should have a MSc. in Physics (preferred) or Engineering. Experience on applied Superconductivity and/or Cryogenics is preferred but not required. The candidate should be able to work independently as well as part of a team.
The Ph.D student will receive an initial one year contract; if the first year is successful the contract will be extended to three more years (four years in total). The envisaged starting date is 1st July 2018 (can be negotiated).
The SPC is a leading institution on research on Plasma Physics and Nuclear Fusion, and belongs to the Basic Science Faculty (FSB) of EPFL. The Superconductivity Group, located on the ground of the Paul Scherrer Institute in Villigen, about 40 km from Zurich and 10 km from the Swiss-German border, has a solid expertise in magnet technology based on both low and high temperature superconductors for fusion and other applications.