Driving intrinsic rotation in tokamaks using up-down asymmetric plasma shaping
Event details
| Date | 15.04.2016 |
| Hour | 10:30 › 11:30 |
| Speaker | Justin Ball, Oxford University & Culham Center for Fusion Energy, UK |
| Location |
PPB 019
|
| Category | Conferences - Seminars |
Recent work demonstrated that breaking the up-down symmetry of tokamaks removes a constraint limiting intrinsic momentum transport, and hence toroidal rotation, to be small [Parra, et al. Phys. Plasmas (2011)]. We show through MHD analysis that low order flux surface shaping (e.g. elongation, triangularity) is optimal for introducing up-down asymmetry throughout the plasma. We then demonstrate a particular tilting symmetry of the flux surface shape in the local nonlinear df gyrokinetic model. This symmetry establishes an important distinction between the momentum transport in tokamaks with mirror symmetric flux surfaces and tokamaks with flux surfaces that lack mirror symmetry. Using GS2, a local df gyrokinetic code that self-consistently calculates momentum transport, we first numerically verify this gyrokinetic symmetry. Then we show the momentum flux calculated by GS2 is consistent with both TCV experimental measurements [Camenen, et al. Phys. Rev. Lett. (2010)] and analytically derived scalings in the limit of high order flux surface shaping. Lastly, we investigate the influence of the Shafranov shift on momentum transport. The results of this work suggest that up-down asymmetry can generate sufficient rotation to stabilize the resistive wall mode in reactor-sized devices.
Practical information
- Informed public
- Free
Organizer
- Prof. P. Ricci
Contact
- Prof. P. Ricci