HR: 15:10h
AN: SA22B-07    [PDF]
TI: Observation and Modeling of Ionospheric Dynamics During Major Solar Flares
AU: * Smithtro, C
EM: smithtro@cc.usu.edu
AF: Center for Atmospheric and Space Sciences, Utah State University 4405 Old Main Hill, Logan, UT 84322-4405 United States
AU: Berkey, T
EM: frank.berkey@usu.edu
AF: Space Dynamics Laboratory, Utah State University 1695 North Research Park Way, Logan, UT 84341 United States
AU: Thompson, D
EM: thompson@cc.usu.edu
AF: Center for Atmospheric and Space Sciences, Utah State University 4405 Old Main Hill, Logan, UT 84322-4405 United States
AU: Sojka, J J
AF: Center for Atmospheric and Space Sciences, Utah State University 4405 Old Main Hill, Logan, UT 84322-4405 United States
AU: Schunk, R W
EM: schunk@cc.usu.edu
AF: Center for Atmospheric and Space Sciences, Utah State University 4405 Old Main Hill, Logan, UT 84322-4405 United States
AB: Ionograms from the Bear Lake Observatory dynasonde show a characteristic enhancement to the E and F1-regions during major solar x-ray flares. The virtual height of the bottom-side F-layer often increases 50-100 km within minutes while fof2 remains relatively unchanged. This effect is believed to result from a sudden increase in solar XUV flux (1-30 nm), causing rapid ionization in the E and F1 regions. By contrast, the F2 region is slower to respond. We attempt to model these dynamics and create synthetic ionograms for comparison with observations using the Time-Dependent Ionospheric Model (TDIM). For solar input to the TDIM, we build a representative flare spectrum using measurements from the Solar EUV Experiment (SEE) instrument on the TIMED spacecraft.
DE: 2435 Ionospheric disturbances
DE: 2443 Midlatitude ionosphere
DE: 2479 Solar radiation and cosmic ray effects
DE: 7519 Flares
SC: SPA - Aeronomy [SA]
MN: 2003 Fall Meeting