HR: 15:15h
AN: SH52A-07    [PDF]
TI: Stormtime Ionospheric Irregularities in SAPS-Related Troughs: Causes of GPS Scintillations at Mid Latitudes
AU: * Mishin, E V
EM: evgenii.mishin@hanscom.af.mil
AF: Boston College, Institute for Scientific research, Chestnut Hill, MA 02467 United States
AU: Burke, W J
EM: william.burke@hanscom.af.mil
AF: AFRL/VSBXP, 29 Randolph Rd, Hanscom AFB, MA 01731 United States
AU: Basu, S
EM: sbasu@bu.edu
AF: Boston University, Center for Space Physics, Boston, MA 02215 United States
AU: Basu, S
EM: santimay.basu@hanscom.af.mil
AF: AFRL/VSBXP, 29 Randolph Rd, Hanscom AFB, MA 01731 United States
AU: Kintner, P M
EM: pmk1@cornell.edu
AF: Cornell University, 302 Rhodes Hall, Ithaca, NY 14853 United States
AU: Ledvina, B
EM: ledvina@cornell.edu
AF: Cornell University, 302 Rhodes Hall, Ithaca, NY 14853 United States
AB: Radio-wave scintillations are space weather effects caused by ionospheric plasma density irregularities. The subauroral ionosphere, at magnetic latitudes corresponding to the northeastern US, is generally free of such irregularities and consequently scintillations. Recently, Basu et al. [JGR, 106, 30389, 2001] and Ledvina et al. [GRL, 29, 10.1029/2002GL014770] reported observations of strong GPS phase and amplitude scintillations at 1.5 GHz at Hanscom AFB, MA and Ithaca, NY during the magnetic storms of 23 September, 1999 and 25 - 26 September, 2001, respectively. We report results of a survey of small-scale plasma density and electromagnetic oscillations detected by DMSP F13, 14, and 15 satellites while flying over the affected regions at altitude of 840 km. Langmuir probe data, sampled at a rate of 24 Hz, show that during the scintillation intervals the amplitudes of density oscillations in the frequency range of 3-10 Hz increased by a factor of 100. The enhanced fluctuations appeared at the poleward edges of large-scale density troughs, embedded within subauroral polarization streams. When Doppler-shifted from spacecraft frames of reference the oscillations correspond to irregularities with spatial scales of 2-0.7 km. Most likely these irregularities are responsible for radio-signal scintillations at frequencies near 1 GHz.
DE: 2788 Storms and substorms
DE: 2799 General or miscellaneous
DE: 6979 Space and satellite communication
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting