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Evolution

All Physics Faculty Publications

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Full-Text Articles in Physics

Modeling The Evolution Of Meso-Scale Ionospheric Irregularities At High Latitudes, Jan Josef Sojka, L. Zhu, M. David, Robert W. Schunk Jan 2000

Modeling The Evolution Of Meso-Scale Ionospheric Irregularities At High Latitudes, Jan Josef Sojka, L. Zhu, M. David, Robert W. Schunk

All Physics Faculty Publications

The modeling of ionospheric plasma density irregularities (ΔN/N) is a necessary first step towards forecasting ionospheric scintillation effects. This modeling challenge is difficult not only because the linear‐nonlinear saturation levels of instabilities are not completely understood but also because ΔN/N often evolves on time scales which are long compared to the characteristic time constants of the instability drivers. In this study, the linear 1‐D gradient drift instability (GDI) is used in a high latitude simulation of ΔN/N evolution. For the first time snapshots (maps) of ΔN/N are presented demonstrating that it is possible to use …


Nonlinear Front Evolution Of Hydrodynamic Chemical Waves In Vertical Cylinders, J. W. Wilder, D. A. Vasquez, Boyd F. Edwards Sep 1997

Nonlinear Front Evolution Of Hydrodynamic Chemical Waves In Vertical Cylinders, J. W. Wilder, D. A. Vasquez, Boyd F. Edwards

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The nonlinear stability of three-dimensional reaction-diffusion fronts in vertical cylinders is considered using the viscous hydrodynamic fluid equations in the limit of infinite thermal diffusivity. A nonlinear front evolution equation is presented and used to examine the transition from nonaxisymmetric to axisymmetric convection observed in experiments performed in cylinders. Comparisons with experiments show excellent agreement in both the shape and speed of the front.