Magneto-Fluid Dynamics Seminar

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Emergent symmetries in low-beta gyrokinetics

Speaker: Ryan White, MIT Plasma Science and Fusion Center

Location: Warren Weaver Hall 905

Date: Tuesday, March 13, 2018, 11 a.m.

Synopsis:

Symmetries are a powerful tool for extracting qualitative information from reduced models. In particular, an asymptotically consistent reduced model must contain all of the symmetries of the first principles description, but the converse is not true: reduced models can have additional symmetries which are an artifact of the simplification achieved by the asymptotic reduction. These emergent symmetries can signal the existence of (approximately) conserved quantitites. In this talk, I will present symmetries of the KREHM model derived by A. Zocco and A. A. Schekochihin. This model, which is formally obtained by considering gyrokinetics in the limit of small beta, possesses many emergent symmetries which are not obvious from physical considerations. We will also discuss how the formal techniques of symmetry analysis are applied to equations with integral relations, which are a ubiquitous feature of reduced kinetic models. Finally, we will show how these symmetries can be used to study the behavior of three dimensional reconnecting systems.