HR: 1340h
AN: SM43B-1224    [Abstracts]
TI: Equatorial Plasma Bubble Detection and Scintillation Specification by the Thermal Plasma Sensor (TPS) on NPOESS
AU: * Basu, S
EM: santimay@aol.com
AF: AF Research Laboratory, 29 Randolph Road, Hansom AFB, MA 01731 United States
AU: Basu, S
EM: sbasu@bu.edu
AF: Boston University, Center for Space Physics, 725 Commonwealth Avenue, Boston, MA 02215 United States
AU: Groves, K
EM: Keith.Groves@hanscom.af.mil
AF: AF Research Laboratory, 29 Randolph Road, Hansom AFB, MA 01731 United States
AU: Starks, M
EM: Michael.Starks@hanscom.af.mil
AF: AF Research Laboratory, 29 Randolph Road, Hansom AFB, MA 01731 United States
AU: Rich, F
EM: Frederick.Rich@hanscom.af.mil
AF: AF Research Laboratory, 29 Randolph Road, Hansom AFB, MA 01731 United States
AB: The thermal plasma sensor (TPS) on the National Polar-orbiting Operational Environmental Satellites System (NPOESS) will perform in-situ measurements of the total ion concentration, the ion concentration fluctuations and the ion temperature. The ion concentration measurements will have a range from less than 10e3 per c.c. to greater than 10e6 per c.c. The DMSP data is used to show that this range of total ion concentration measurements will be adequate to detect the smallest as well as the deepest equatorial plasma bubbles. The detection of deep plasma bubbles will indicate the disturbed state of the equatorial electrodynamics in the presence of much enhanced zonal electric fields. Furthermore, the bubbles generally indicate the presence of steep gradients in the total electron content of the ionosphere that may disable the GPS-based aircraft navigation systems currently undergoing development at equatorial latitudes. The TPS sensor will have the ability to measure the fluctuations in the electron concentration, DN/N, less than 0.1 per cent over distances of 25 km to as large as 50 per cent. These two bounds of DN/N in the equatorial region during the post-sunset hours correspond to weak VHF scintillations and saturated GHz scintillations respectively. It is well-known that with the 32 Hz sampling of the TPS data, the Fourier spectra of the ion concentration fluctuation data extends only to a Nyquist scale-length of 500 m. By using the high frequency comb filter outputs of the TPS sensor, the spectrum can, however, be extended to tens of meter scales, a decade smaller than the Fresnel dimension of GHz scintillation. It is shown that in the framework of radio wave diffraction theory, such data, in combination with the electron density profile measurements made by NPOESS can be used to specify scintillations in the range of VHF to GHz.
DE: 2415 Equatorial ionosphere
DE: 2437 Ionospheric dynamics
DE: 2481 Topside ionosphere
DE: 2494 Instruments and techniques
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005