Title : Simulations of plasma filaments in stellarator geometries with BSTING
Speaker Name: Brendan Shanahan
Speaker Institution : Max Planck Institut fur Plasmaphysik, Greifswald
Notes:Abstract : Wendelstein 7-X has exhibited novel edge and scrape-off-layer physics in the first experimental campaign. Edge filaments [1] and high frequency heat flux variations [2] are among many new observations which merit numerical investigation. While there are several edge fluid turbulence frameworks for tokamak geometries, the complicated nature of a stellarator edge and scrape-off-layer has as yet inhibited the development of a fluid turbulence framework for stellarator geometries. One of these simulation frameworks written for tokamak geometries, BOUT++ [3], is also able to simulate phenomena such as ELMs, magnetic reconnection, plasma transport and neutral interactions. The BSTING project [4] has extended BOUT++ to stellarator geometries, thereby providing the first nonlinear fluid simulation framework for non-axisymmetric geometries.
Here we outline recent developments in the BSTING project, including a newly implemented curvilinear grid system suitable for stellarator edge magnetic topology, and present simulations of plasma filaments in stellarator geometries [4]. Results from simulations of filaments dynamics in non-uniform drive scenarios [5] and in regions of strongly-varying connection lengths, such as the view from the planned Gas Puff Imaging diagnostic on W7-X, are also included. Initial investigations of ablated pellet interaction using the Hermes [6] fluid turbulence model are presented. Finally, a discussion of the relevance and application of these methods to Wendelstein 7-X edge turbulence scenarios is provided.
[1] G. Kocsis, et al., 44th EPS Conference on Plasma Physics (2017). [2] G. A. Wurden, et al., Nuclear Fusion 57, 056036 (2017). [3] B D Dudson et al., Comp. Phys. Comm. 180 9 1467-1580 (2009). [4] B Shanahan et al., Plasma Phys. Control. Fusion 61 0250007 (2019). [5] B Shanahan et al., J. Phys.; Conf. Series 1125 012018 (2018). [6] B D Dudson and J Leddy Plasma Phys. Control. Fusion 59 054010 (2017). Title of Event: Edits: