HR: 0800h
AN: SA21B-0357    [Abstracts]
TI: Impact of the Bastille Day Solar Flare on the Low- to Mid-Latitude Ionosphere
AU: * Huba, J
EM: huba@ppd.nrl.navy.mil
AF: Naval Research Laboratory, Plasma Physics Division, Washington, DC 20375 United States
AU: Warren, H
EM: hwarren@ssd5.nrl.navy.mil
AF: Naval Reserch Laboratory, Space Science Division, Washington, DC 20375 United States
AU: Joyce, G
EM: joyce@ppd.nrl.navy.mil
AF: George Mason University, 1222 Braddock Road, Fairfax, VA 22321 United States
AB: We study the impact of the Bastille Day solar flare radiation on the low- to mid-latitude ionosphere. The methodology is as follows. We develop an EUV irradiance spectrum based upon observations for the Bastille Day flare. Since solar irradiance observations typically do not have the cadence necessary to follow the evolution of a flare, we have developed techniques for computing flare spectra from the available solar data. We then use this spectrum in the NRL three-dimensional ionosphere model SAMI3 to obtain the global impact of the flare on the mid- to low-latitude ionosphere. We assess the flare's impact by comparing simulation results with and without the solar flare enhanced EUV spectrum. A previous study using the NRL two dimensional ionosphere model SAMI2 and a more simplistic EUV spectrum of the Bastille Day storm found that flare radiation can increase the F-region ionosphere density by up to 50% [Meier et al., Geophys. Res. Lett. 29, 10.1029/2001GL013956, 2002]. \medskip \noindent Research supported by ONR.
DE: 2423 Ionization mechanisms
DE: 2435 Ionospheric disturbances
DE: 2443 Midlatitude ionosphere
DE: 2447 Modeling and forecasting
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting