Stochastic Lagrangian dynamics for charged flows in the E-F regions of ionosphere

We develop a three-dimensional numerical model for the E-F region ionosphere and study the Lagrangian dynamics for plasma flows in this region. Our interest rests on the charge-neutral interactions and the statistics associated with stochastic Lagrangian motion. In particular, we examine the organiz...

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Bibliographic Details
Published in:Physics of plasmas 2013-03, Vol.20 (3), p.32305
Main Authors: Tang, Wenbo, Mahalov, Alex
Format: Article
Language:English
Subjects:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ASTROPHYSICS
DENSITY
E REGION
F REGION
GRAVITY WAVES
LAGRANGIAN FUNCTION
LYAPUNOV METHOD
NUMERICAL ANALYSIS
PLASMA DENSITY
STATISTICS
STOCHASTIC PROCESSES
THREE-DIMENSIONAL CALCULATIONS
VELOCITY
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Summary:We develop a three-dimensional numerical model for the E-F region ionosphere and study the Lagrangian dynamics for plasma flows in this region. Our interest rests on the charge-neutral interactions and the statistics associated with stochastic Lagrangian motion. In particular, we examine the organizing mixing patterns for plasma flows due to polarized gravity wave excitations in the neutral field, using Lagrangian coherent structures (LCS). LCS objectively depict the flow topology-the extracted attractors indicate generation of ionospheric density gradients, due to accumulation of plasma. Using Lagrangian measures such as the finite-time Lyapunov exponents, we locate the Lagrangian skeletons for mixing in plasma, hence where charged fronts are expected to appear. With polarized neutral wind, we find that the corresponding plasma velocity is also polarized. Moreover, the polarized velocity alone, coupled with stochastic Lagrangian motion, may give rise to polarized density fronts in plasma. Statistics of these trajectories indicate high level of non-Gaussianity. This includes clear signatures of variance, skewness, and kurtosis of displacements taking polarized structures aligned with the gravity waves, and being anisotropic.
ISSN:1070-664X
1089-7674
DOI:10.1063/1.4794735