Available positions

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 .

Thank you.

Experimental physics on the TCV tokamak

Experimental physics on the TORPEX device

Experimental physics on the JET tokamak

Plasma Physics Theory

Superconductivity for fusion

Open positions in experimental physics on the TCV tokamak

  • Study and optimization of electron density profiles, turbulence characteristics and instabilities in the edge and pedestal of TCV plasma

Contact person:  Dr. MER S. Coda or Dr. L. Porte

Observations [1] 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 [2] and Doppler backscattering (DBS) [3] 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.

[1] O. Sauter et al, Phys. Plasmas 21, 055906 (2014) [2] P. Molina-Cabrera et al, to be submitted to Rev. Sci. Instrum. [3] P. Molina-Cabrera et al, to be published in Rev. Sci. Instrum. (2018)

  • Divertor Spectroscopy

Contact person:  Dr. MER B.P. Duval

Atomic physics (the study of light emission/absorption) processes play a strong role in the divertor (exhaust) of thermonuclear devices. The power handling of high power, high temperature, plasma configurations such as those exploited in Tokamaks like TCV remains critical and topical to an economically successful fusion reactor. Most of the power from such a reactor is directed towards the divertor where it interacts with the machine structures. If unhandled, the power levels involved easily exceed not only the long but the short term survival of these machine structures. Multi-chord spectroscopic systems simultaneously monitor several spectral lines from the main plasma (Hydrogen, Deuterium) and impurities. The analysis of the line intensities, line ratios, spectroscopically resolved spectral line shapes etc. provides highly valuable information on local plasma conditions, that when incorporated into collisional-radiative models, together with plasma physics knowledge, can be employed to understand the efficiency of the divertor power handling. This thesis project would begin by assuming control and operation of two existing spectrometers, operating them over a range of TCV discharges and extending the present collisional-radiative model used to interpret the data. New observation optics, for TCV’s divertor upgrades, new spectrometers etc. are expected to be implemented to further extend the measurable plasma parameters that are extremely important to TCV’s growing divertor physics group.

  • 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.

  • 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 of tokamaks, including magnetic control, plasma profile control, as well as advanced topics such as scenario control, monitoring and supervision.

  • Suprathermal electron physics in the TCV tokamak

Contact person: MER Stefano Coda

Suprathermal electrons mediate the physics of ECRH and ECCD and play a strong role in MHD instabilities. Runaway electrons are key to the physics of disruptions and are a major concern for fusion reactors. TCV has a new hard X-ray tomographic spectrometer and several complementary suprathermal electron diagnostics, and two in-house suites of Fokker-Planck quasilinear codes with synthetic diagnostics. There are ripe opportunities for a thesis involving joint experimental and modelling work, with considerable freedom in emphasis and detail.
Further details here

  • 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.

Open positions in experimental physics on the TORPEX device

  • Suprathermal ion dynamics in turbulent plasmas

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.

Open positions in experimental physics on the JET tokamak

  • Measurement and interpretation of TAE in JET, including DT experiments.

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.

Plasma Physics Theory

  • Gyrokinetic turbulence simulations with advanced numerical techniques

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.

Open positions in superconductivity for fusion

  • Applied superconductivity: strain characterisation of Nb3Sn superconductors for DEMO tokamak

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.