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Activities on FTU Tokamak

IFP contribution to Frascati Tokamak Upgrade experiment regards the management and use of the additional heating system (called “FTU ECRH”) based on waves at electron cyclotron (EC) frequency. With this system, designed and realized by IFP, 4 microwave beams are injected for an overall power of 1.6MW at a frequency of 140 GHz resonant at 5T a magnetic field. The system consists of 4 microwave sources (gyrotron), supplying 500KW each for 0.5s; the power is transferred by overmoded corrugated waguides; two lanching antennas are realized with moving mirrors, one of them used also for power deposition experiments with real time control. The mirrors focus the microwaves beams in the plasma, where local power density of 70 MW/m3 can be reached. The gyrotron power supply system allows sinusoidal or squared wave power modulation with maximum frequency 10 kHz. As a recent development of the power supply, the power generation system could be used as part of a feedback system for real time control experiments of plasma parameters. 

ECRH experiment, started in 1994 with a single power source with a short impulse duration (15ms), has reached full operation in 1997 and has been completed in 2003, when the nominal performances of the project have been achieved (1.6MW in the plasma). Studies of additional heating physics at the electron cyclotron resonance are performed together with studies of future applications to thermonuclear plasmas. Two launching antennas are available at the moment.

Main research areas are:

  • Propagation and absorption of EC waves in high electron density plasma (> 1020m-3) with electron heating of collisional plasmas
  • Active real time stabilization with ECH/ECCD of MDH instabilities (m=1 order sawteeth and “resistive tearing mode”)
  • Study of heat transport in stationary conditions in presence of perturbative modes
  • Absorption of EC waves from sovrathermal electrons with generation of non-inductive current
  • Possibile effects of plasma disruption mitigation with EC waves
  • Development of a diagnostic for measuring ion the temperature with Collective Scattering effects at high frequency (CTS) and investigation od peculiar phenomena (i.e. parametric decays of EC waves)

 

Besides high frequency plasma-wave interaction, other arguments of collaborations and studies on FTU are:

  • EC assisted "break-down" and "current ramp-up" 
  • Modification of particle transport in presence of EC heating
  • Current dirve efficiency for Lower Hybrid waves
  • Formation of electron transport barriers with lower hybrid and EC waves combination
  • Effects on electron cyclotron emission from high temperature plasma
  • Impurity transport in high temperature plasma
 
 

Activities on JET Tokamak

IFP has an active role on the following areas:

  • Study of ion and electron turbulent heat transport: experiments in D and H plasmas, model validation, quasi-linear simulations and gyro-kinetic simulations
  • Study of impurity transport, control of accumulation, effects of impurities on thermal transport, gyro-kinetic simulations
  • Study of particle transport and density peaking using gas puff modulation
  • Neutron and gamma ray spectroscopy diagnostics for Deuterium and Deuterium-Tritium plasmas
  • Development of new compact diagnostics: GCU (Gamma ray camera Upgrade) and VNS (Vertical Neutron Spectrometer) projects
  • Analysis of discharges in H-mode (high confinement) with NBI and ICRH heating for the study of the effects of NTMs on the transport coefficients modeled in the European Transport Solver (ETS) in the framework of the EUROfusion WPCD task 
  • Study of the magnetohydrodynamic activity and of its relationship with sudden and uncontrolled plasma terminations
  • Study of the electron energy distribution function at very high plasma temperature
  • Analysis of ammonia formation and nitrogen retention in N2-seeded discharges as well as during regeneration of the cryo-pumps
  • Upgrade and application of the dust trajectory code DUSTTRACK to the description of the mobilisation and fate of bunches of dust particles in JET experimental plasma configurations.
  • Development of dust (W, Fe) ablation models and application to Transient Impurity Events (TIEs) occurrences in the SOL of JET.
 

Activities on AUG and TCV Tokamaks

IFP has the scientific responsibility for the Disruption Avoidance area and participates in experiments on the AUG and TCV tokamaks.

Furthermore, IFP researchers are involved in the following topics:

  • Asdex Upgrade (AUG)

Validation of transport models on hybrid scenarios

 

Validation of the module to describe the NTMs in the European Transport Solver code workflow, for the control of magneto-hydrodynamic instabilities with EC waves

Study of the dynamics of NTM and control by EC power injection

  • Tokamak à Configuration Variable (TCV)

Experiments of plasma assisted startup by EC wave injection

Experiments with plasmas in the presence of "runaway" electrons

There is also a scientific collaboration between IFP and the Swiss Plasma Center (SPC) in Lausanne, within which IFP researchers provide know-how and support in various areas including:

  1. Design of high power mm-wave components
  2. Support in the management of the TCV ECRH system during TCV operations
  3. Exploitation of experiments on TCV tokamak
  4. Microwave component testing at SPC-EPFL

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