NSF Org:	AGS Division of Atmospheric and Geospace Sciences
Recipient:	SOUTHWEST RESEARCH INSTITUTE
Initial Amendment Date:	September 14, 2005
Latest Amendment Date:	July 25, 2008
Award Number:	0518748
Award Instrument:	Continuing Grant
Program Manager:	Cassandra G. Fesen AGS  Division of Atmospheric and Geospace Sciences GEO  Directorate for Geosciences
Start Date:	September 15, 2005
End Date:	October 31, 2008 (Estimated)
Total Intended Award Amount:	$0.00
Total Awarded Amount to Date:	$299,569.00
Funds Obligated to Date:	FY 2005 = $0.00 FY 2006 = $0.00 FY 2007 = $0.00
History of Investigator:	Rudy Frahm (Principal Investigator) rfrahm@swri.edu Geoffrey Crowley (Former Principal Investigator)
Recipient Sponsored Research Office:	Southwest Research Institute 6220 CULEBRA RD SAN ANTONIO TX  US  78238-5166 (210)522-2231
Sponsor Congressional District:	20
Primary Place of Performance:	Southwest Research Institute 6220 CULEBRA RD SAN ANTONIO TX  US  78238-5166
Primary Place of Performance Congressional District:	20
Unique Entity Identifier (UEI):	PB11V1KH3KV4
Parent UEI:	PB11V1KH3KV4
NSF Program(s):	AERONOMY, Upper Atmospheric Facilities
Primary Program Source:	app-0105  app-0106  app-0107
Program Reference Code(s):	4444, 9196, EGCH
Program Element Code(s):	152100, 420200
Award Agency Code:	4900
Fund Agency Code:	4900
Assistance Listing Number(s):	47.050

ABSTRACT

A Doppler High Frequency (HF) radar is placed at the Jicamarca Peru Incoherent Scatter Radar Facility for the purpose of untangling the processes that lead to the onset of equatorial plasma bubbles (EPBs), and in turn to scintillations of radio signals traversing the ionosphere, including GPS signals. The spectra and propagation of ionospheric perturbations just below the F-region peak are characterized, and their relationship to EPBs observed at Jicamarca is determined. The variability of vertical ion drift in the enhanced ion density preceding the neutral wind reversal is determined during solar minimum conditions, and the relationship of that variability to equatorial plasma bubble onset is determined. The extent to which neutral winds modulate the occurrence of EPBs, and possibly override otherwise effective triggering mechanisms is also evaluated using data from nearby Fabry-Perot interferometers. The determined relationships between plasma perturbations below the F-region ionospheric peak, variability of the vertical ion drift, the neutral wind, and EPB onset are finally used to in an attempt to predict EPB generation, along with associated radio scintillations.

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