Accession Number:

ADA564533

Title:

Numerical Simulation and Forecast of Equatorial Spread F Under Realistic Postsunset Conditions

Descriptive Note:

Final rept. Apr 2009-Jan 2012

Corporate Author:

CORNELL UNIV ITHACA NY DEPT OF EARTH AND ATMOSPHERIC SCIENCES

Personal Author(s):

Report Date:

2012-01-30

Pagination or Media Count:

16.0

Abstract:

A fully three-dimensional numerical simulation of plasma density irregularities in the postsunset equatorial F region ionosphere leading to equatorial spread F ESF has been developed. The simulation evolves under realistic background conditions including bottomside plasma shear flow and vertical current. It has been initialized and driven in accordance with background measurements obtained from the Air Force CNOFS satellite, the Jicamarca Radio Observatory, the Altair radar on Kwajalein, and other instruments. Simulations are seeded with white noise alone and are, in that sense, agnostic with respect to the required, underlying seed mechanism. A combination of generalized Rayleigh Taylor gRT and collisional shear instability CSI has been found to produce growing waveforms with key features that agree with satellite and ground-based radar observations in several important respects, including their gross morphology, development rates, and magnetic signatures. The transient response of CSI is consistent with the observation of bottomside waves with wavelengths close to 30 km, whereas the steady-state behavior of the combined instability can account for the 100 km wavelength waves that predominate in the F region.

Subject Categories:

  • Plasma Physics and Magnetohydrodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE