HR: 0830h
AN: SA21A-07    [Abstracts]
TI: Effect of E-Region Ionospheric Electric Field on Meteor Plasma Trails
AU: * Dimant, Y S
EM: dimant@bu.edu
AF: Boston University, Center for Space Physics, 725 Commonwealth Ave., Boston, MA 02215 United States
AU: Oppenheim, M M
EM: meerso@bu.edu
AF: Boston University, Center for Space Physics, 725 Commonwealth Ave., Boston, MA 02215 United States
AU: Dyrud, L
EM: ldyrud@bu.edu
AF: Boston University, Center for Space Physics, 725 Commonwealth Ave., Boston, MA 02215 United States
AU: Milikh, G M
EM: milikh@astro.umd.edu
AF: Univeristy of Maryland, Department of Astronomy, College Park, MD 20742 United States
AB: Meteoroids penetrating the Earth's ionosphere leave behind dense plasma trails. Electron density irregularities within these trails create a significant part of the total radar clutter from the E-region ionosphere. These irregularities are partially caused by destabilizing electric fields which develop in or near the plasma trail. To model the radar echoes for meteor and atmospheric diagnostics, we need to properly understand the underlying physical cause of these electric fields. In this talk, we will introduce a quantitative model of the meteor-induced polarization electric fields for fully 3-D trails in the presence of external magnetic and DC electric fields in the E region. For the cases when a sufficiently strong DC electric field perpendicular to the geomagnetic field or strong neutral winds exist, we have calculated the 3-D spatial distribution of the polarization electric field around the trail. This electric field may reach significant values (tens mV/m and more) and may excite instabilities that cause non-specular radar echoes. This may help explain non-specular echoes which persist for a long time after the meteoroid has gone [Chapin and Kudeki, JGR, 99, 8937 (1994)]. In this case, the near-trail electric field increases with the meteoroid size until, for sufficiently big meteoroids, the linear plasma density in the trail reaches 10¹⁵--10¹⁶ m^-1, and the polarization electric field saturates. The additional polarization electric field may also result in strong heating of electrons which in turn may lead to a modified rate of plasma trail diffusion and an additional airglow. Combining our theory with radar observations of specular and non-specular echoes should yield useful information about meteor trails and the surrounding atmosphere.
DE: 2435 Ionospheric disturbances
DE: 2467 Plasma temperature and density
DE: 2471 Plasma waves and instabilities
DE: 2712 Electric fields (2411)
DE: 6245 Meteors
SC: SPA-Aeronomy [SA]
MN: 2005 Joint Assembly