Symmetries of a reduced fluid-gyrokinetic system

• Main Authors: White, Ryan Lee (Author), Hazeltine, R.D (Author), Gomes Loureiro, Nuno F (Author)
• Other Authors: Massachusetts Institute of Technology. Plasma Science and Fusion Center (Contributor)
• Format: Article
• Language: English
• Published: Cambridge University Press (CUP), 2020-03-25T18:13:09Z.
• Subjects: Article
• Online Access: Get fulltext

 Symmetries of a fluid-gyrokinetic model are investigated using Lie group techniques. Specifically, the nonlinear system constructed by Zocco & Schekochihin (Phys. Plasmas, vol. 18, 2011, 102309), which combines nonlinear fluid equations with a drift-kinetic description of parallel electron dynamics, is studied. Significantly, this model is fully gyrokinetic, allowing for arbitrary kρi, where k is the perpendicular wave vector of the fluctuations and ρi the ion gyroradius. The model includes integral operators corresponding to gyroaveraging as well as the moment equations relating fluid variables to the kinetic distribution function. A large variety of exact symmetries is uncovered, some of which have unexpected form. Using these results, new nonlinear solutions are constructed, including a helical generalization of the Chapman-Kendall solution for a collapsing current sheet.