Detailed measurements of oscillating zonal flows in the TCV tokamak
Event details
| Date | 18.02.2013 |
| Hour | 10:30 › 11:30 |
| Speaker | Dr. K. de Meijere, CRPP-EPFL |
| Location |
PPB 019
|
| Category | Conferences - Seminars |
The geodesic acoustic mode (GAM), which is a coherently oscillating zonal flow in turbulent toroidal plasmas, has been characterised in detail in the TCV tokamak by simultaneous measurement of multiple fluctuating quantities. Multi-point, radially localised measurements of electron density and temperature fluctuations were performed using tangential phase-contrast imaging (TPCI) and correlation ECE, respectively. A single-channel microwave backscattering system was used to measure ExB flow fluctuations. The physical principles and implementation of these instruments are briefly discussed. The measurements show that the GAM is present in the outer 30% of the plasma and takes the form of a spatially coherent, outward propagating wave. These observations are in good agreement with electrostatic, gyrokinetic simulations with the ORB5 code. A novel observation is that the magnetic component of the GAM is measurable outside the plasma, allowing experimental confirmation of the theoretically expected global mode structure.
Practical information
- Expert
- Free
Organizer
- Prof. P. Ricci, CRPP-EPFL
Contact
- Prof. P. Ricci, CRPP-EPFL