HR: 0800h
AN: SA31A-07    [Abstracts]
TI: On the efficiency factor for Jicamarca incoherent scatter measurements
AU: * Rodrigues, F S
EM: fsr5@cornell.edu
AF: Cornell University, 2122 Snee Hall, Ithaca, NY 14853, United States
AU: Nicolls, M J
EM: michael.nicolls@sri.com
AF: SRI International, Center for Geospace Studies 333 Ravenswood Ave., Menlo Park, CA 94025, United States
AU: Hysell, D L
EM: dlh37@cornell.edu
AF: Cornell University, 2122 Snee Hall, Ithaca, NY 14853, United States
AU: Chau, J L
EM: jchau@jro.igp.gob.pe
AF: Jicamarca Observatory, Instituto Geofísico del Peru, Lima, Peru
AB: Sulzer and Gonzalez (1999) found that electron coulomb collisions have an important effect on the incoherent scattering of radio waves by a plasma at small aspect angles. The primary effect of electron coulomb collisions on incoherent scattering at small aspect angles is the narrowing of the spectrum. Another interesting effect of the collisions is the control of the efficiency factor (Milla and Kudeki, 2006), which is defined as a proportionality factor between the plasma electron density and the normalized total scattering cross section. For unmagnetized plasmas or the case of large aspect angles, the efficiency factor is approximately 1/(1+Te/Ti). Milla and Kudeki (2006), however, pointed out that the efficiency factor is far more complicated for small aspect angles. An analytical expression of the efficiency factor for small aspect angles does not exist yet. In this work, proper efficiency factor for Jicamarca measurements were obtained using numerical integration of the incoherent scatter spectrum including magnetic field and coulomb effects. The results were used to correct backscattered power profiles measured at Jicamarca. Corrected power profiles were compared with electron density profiles measured simultaneously using Faraday rotation. A good agreement between corrected power profiles and electron density profiles has been found. This result not only improves electron density measurements at Jicamarca, but also validates the formulation of Woodman (2006) and Kudeki and Milla (2006) based on the coulomb effects discovered by Sulzer and Gonzalez (1999).
DE: 2415 Equatorial ionosphere
DE: 2467 Plasma temperature and density
DE: 2494 Instruments and techniques
DE: 6969 Remote sensing
DE: 6974 Signal processing (0674)
SC: SPA-Aeronomy [SA]
MN: 2007 Joint Assembly