HR: 0800h
AN: SA21C-0373    [Abstracts]
TI: Generation and evolution of heater-induced density irregularities due to self-focusing instabilities in the ionosphere
AU: Gondarenko, N A
EM: Ngondare@Glue.umd.edu
AF: University of Maryland, IREAP, College Park, MD 20742 United States
AU: * Guzdar, P N
EM: guzdar@umd.edu
AF: University of Maryland, IREAP, College Park, MD 20742 United States
AU: Ossakow, S L
EM: ossakow@ccs.narl.navy.mil
AF: Naval Research Laboratory, Code 6700, Washington, DC 20375 United States
AU: Milikh, G M
EM: milikh@astro.umd.edu
AF: University of Maryland, Department of Astronomy, College Park, MD 20742 United States
AB: Simulations of the generation and evolution of the ionospheric density irregularities due to self-focusing instabilities (SFI) are presented. A nonlinear, self-consistent development of the instabilities is studied with the 2D model of HF radio wave propagation in inhomogeneous magnetized plasmas. The full-wave model is coupled with the density and temperature equations. In these studies, the beam is incident vertically or tilted to the magnetic zenith direction. Our results demonstrate that irregularities generated and developed due to a local heating of the anisotropic ionospheric plasma are density depletions (striations) with a strong enhancement of electron temperature inside striations elongated along magnetic field lines. The reflection point of the ordinary wave is shifted upward with increasing density perturbations. During the evolution of the SFI, the formation of bunches of striations is observed. The number of 0.4-4 km bunch scale irregularities is increased when the beam is tilted to the magnetic zenith direction. The presented results are relevant to the experiments carried out at mid-latitude SURA HF heating facility, Russia and at high-latitude facility near Tromso, Norway
DE: 2403 Active experiments
DE: 2439 Ionospheric irregularities
DE: 2487 Wave propagation (6934)
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting