Missions

The work will consist in qualifying and implementing a new Comb Doppler Reflectometer designed by the LPP group. This diagnostic is based on scattering of electromagnetic waves in the micro-wave range; it allows to probe turbulence on a broad range of scales and determine fluctuations velocity through Doppler effect. The new system source produces a frequency comb to probe several cutoff layers at different radial locations simultaneously, to measure instantaneous radial profiles, or study the turbulence spatio-temporal dynamics, fluctuations radial structure or propagation.
The qualification will be done at the lab in Polytechnique, implementation and in situ tests will follow on the tokamak WEST at Cadarache, where this instrument should be installed.

Activités

- Buiding and testing of a Frequency Comb Doppler Reflectometer.
- implementation on the WEST tokamak, Cadarache
- First data processing tools for the new system
- Writing and presentation of the results of this study

Compétences

- Education and experience in plasma physics and/or microwave measurement systems
- experience in experimental campaign on a tokamak
- Matlab/Python programming applied to control and analysis tools.
- Communication and teamwork skills.
- Autonomy, organizational skills and ability to report

Contexte de travail

The mission will be conducted in the framework of a collaboration between LPP/Ecole Polytechnique and CEA/IRFM.
The Fusion Plasmas Group at LPP develops experimental and theoretical studies of plasma turbulence. In particular the team designs fluctuation diagnostics based on microwave or optical range wave scattering (Doppler reflectometry) and operates them on different tokamaks in Europe: WEST (Cadarache) and TCV (Swiss Plasma Center, EPFL). They allow to probe turbulence at different scales and trace fluctuations to infer their velocity through Doppler effect. This is a well suited diagnostic to study turbulence flows interaction.
CEA IRFM (Institut de Recherches sur la Fusion Magnétique) at Cadarache operates the WEST tokamak ("Tungsten (W) Environment in Steady-state Tokamak", upgrade of the former Tore Supra including a divertor to study and mitigate power exhaust) and develops experiments and state of the art models to prepare ITER operation.

Contraintes et risques

Missions will be necessary between the LPP et IRFM for tests and implementation