HR: 12:10h
AN: A52B-12    [Abstracts]
TI: Tempests in the Troposphere and in Tokamaks: New Insights From Comparative Physics
AU: * Ball, R
EM: Rowena.Ball@anu.edu.au
AF: The Australian National University, Mathematical Sciences Institute, Building 27, The Australian National University, Canberra, ACT 0200, Australia
AU: Frederiksen, J S
EM: Jorgen.Frederiksen@csiro.au
AF: CSIRO-Marine and Atmospheric Research, CSIRO-Marine and Atmospheric Research, Aspendale, Vic 3195, Australia
AU: Horton, W
EM: horton@physics.utexas.edu
AF: The University of Texas Austin, Institute for Fusion Studies, The University of Texas Austin, Austin, Tex TX 78712, United States
AB: The persistent patterns of disturbance stream function contours that mark winter storm tracks in mid latitudes, computed from a two layer quasi geostrophic model (J. S. Frederiksen, J. Atm. Sci. 39, 969, 1982), bear a striking resemblance to the patterns of perturbed electrostatic potential contours in poloidal cross sections of a magnetic tokamak plasma (Y. Kishimoto et al, Phys. Plasma 3, 1289, 1996). At first sight these are two vastly different physical systems, yet in both the flows are structured by temperature gradient driven convection. Both types of flow are quasi two-dimensional, but for quite different reasons. In the case of the stratified, rotating flows comprising the atmosphere the horizontal scale is large compared with the vertical scale, while in magnetized plasmas the converse holds. Does this affect the location of enhanced eddy activity? In other words, are the similarities between the systems more important than the manifest differences? In this work we make a systematic comparison of the physics governing baroclinic instabilities in the atmosphere and ion temperature gradient instabilities in plasmas, and examine the stability properties of the equations of motion for both flow fields. We find that the evolution and location of storm tracks is a robust and resilient phenomenon that can be modeled and simulated using a relatively simple proxy. This allows us to predict and compare transport in both systems from much simpler models than have been used to date. The analogs of the plasma Bohm and gyro-Bohm diffusivities are given for the baroclinic instability.
DE: 3314 Convective processes
DE: 3319 General circulation (1223)
DE: 4460 Pattern formation
DE: 4485 Self-organization
DE: 4490 Turbulence (3379, 4568, 7863)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting