High-order finite-element simulations of forced and decaying Hasegawa-Mima turbulence

Simulations of neutral-fluid, two-dimensional turbulence in which localized forcing is balanced by linear damping have provided valuable insight into the physical mechanisms that underpin the dual spectral cascades [1]. We extend these forcing and damping terms to the regime of plasmas characterized by the viscous Hasegawa-Mima (HM) equation. The high-order MFEM finite-element framework is used to solve the governing equations. The plasma length scale and the background plasma gradient are varied in the HM model so as to sufficiently differentiate the turbulence dynamics from the neutral-fluid case. Emphasis is placed on understanding deviations of the HM turbulence from relatively recent neutral-fluid results. As such, we investigate the multiscale strain and vorticity interactions that drive the inverse cascade, the energy condensation state of large scales, logarithmic corrections and scalings for the forward cascade, and the extent of co-existing inertial ranges. [1] G. Boffetta & R. E. Ecke, Annu. Rev. of Fluid Mech., Vol. 44:427-451, 2012.