"Evolution of Zonal Flows from Turbulence in Confined Plasmas and Giant Planets," by Klaus Hallatschek (MPI and TU Munich)

Date: 
Friday, May 16, 2014 - 1:00pm to 2:00pm
Series: 
Plasma Seminars

Plasma Seminar

Friday, May 16, 2014
1:00 PM
Location: IDRE Portal, 5628 Math Sciences Building

Guest Speaker: Klaus Hallatschek (Max Planck Institute for Plasma Physics and Technical University Munich)

Talk Title: "Evolution of Zonal Flows from Turbulence in Confined Plasmas and Giant Planets"

Abstract:

According to everyday experience, turbulence destroys large scale structures by subdividing them into successively smaller ones until they dissipate. A strikingly different behavior is exhibited by the seemingly utterly disparate cases of the convective turbulence in magnetized plasmas, such as tokamaks intended for nuclear fusion, and in giant gas planets, such as Jupiter: Small vortices merge into larger ones, eventually ending up in system spanning flows, which, in the case of Jupiter, cause the well known east-west stripe pattern. The common ingredient in the two systems is a strong alignment of the turbulent eddies respectively along the magnetic field and the axis of rotation. Computer simulations of the two systems show that despite the chaotic nature of the turbulence, the time evolution of the zonal flows itself is rather deterministic but varies qualitatively depending on the fully nonlinear properties of the turbulence, and can exhibit a memory effect. The flows in turn have repercussions for the turbulence as well, leading for instance to transport modulations in tokamaks and turbulence bursts in the giant planets. Apart from the commonalities between the two systems owing to the eddy alignment, there are also differences due to the complex geometry of confined plasmas, which imprints a 3D structure on the zonal flows and creates oscillating global flows.