Bulletin of the American Physical Society
59th Annual Meeting of the APS Division of Plasma Physics
Monday–Friday, October 23–27, 2017; Milwaukee, Wisconsin
Session QI2: Turbulence/Waves
3:00 PM–5:00 PM,
Wednesday, October 25, 2017
Chair: Mike Brown, Swarthmore College
Abstract: QI2.00002 : Intermittency, Anisotropy and the onset of reconnection in strong Alfv\'enic turbulence
3:30 PM–4:00 PM
(University of New Hampshire)
On length scales larger than the ion gyroradius, the turbulence in a plasma with a strong mean magnetic field may be modelled using the equations of reduced magnetohydrodynamics, which describe the evolution of Alfv$\'e$nic fluctuations propagating up and down the magnetic field. This (strongly nonlinear) turbulence is (i) ``critically balanced" - anisotropic with respect to the direction of the local mean magnetic field, (ii) ``aligned" - vector fluctuations in the fields in the perpendicular plane point in the same direction to within a small angle, and the structures are highly sheet-like, (iii) highly intermittent - the shape of the probability distributions of many (but not all!) turbulent quantities depends on scale in a non-trivial way. I will discuss the work we have performed connecting these phenomena, and the resulting statistical model for the Alfv$\'e$nic turbulence we have developed. Finally, I will discuss recent results concerning the onset of reconnection at the small scales of Alfv$\'e$nic turbulence, and the subsequent disruption of the sheet-like turbulent structures at these scales. This dramatically affects the turbulent cascade at small scales, and may provide a resolution to recent disagreements as to the value of asymptotic spectral index of the turbulence.
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