HR: 0800h
AN: SA31A-1106    [Abstracts]
TI: Recent Incoherent Scatter Radar Experiments and Results at Arecibo
AU: * Aponte, N
EM: naponte@naic.edu
AF: Arecibo Observatory, HC3 Box 53995, Arecibo, PR 00612
AU: Sulzer, M P
EM: sulzer@naic.edu
AF: Arecibo Observatory, HC3 Box 53995, Arecibo, PR 00612
AU: Nicolls, M J
EM: mjn25@cornell.edu
AF: School of Electrical and Computer Engineering, Cornell University, Rhodes Hall, Ithaca, NY 14853
AU: Bhatt, A N
EM: anb22@cornell.edu
AF: School of Electrical and Computer Engineering, Cornell University, Rhodes Hall, Ithaca, NY 14853
AU: Gerken, E A
EM: eag48@cornell.edu
AF: School of Electrical and Computer Engineering, Cornell University, Rhodes Hall, Ithaca, NY 14853
AU: Vlasov, M
EM: mv75@cornell.edu
AF: School of Electrical and Computer Engineering, Cornell University, Rhodes Hall, Ithaca, NY 14853
AU: Wong, V K
EM: vkw2@cornell.edu
AF: School of Electrical and Computer Engineering, Cornell University, Rhodes Hall, Ithaca, NY 14853
AU: Nikoukar, R
EM: nikoukar@uiuc.edu
AF: Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Coordinated Science Laboratory, 1308 West Main, Urbana, IL 61801
AU: Adamson, E T
EM: eric_adamson@hotmail.com
AF: Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775-7320
AU: Bristow, W A
EM: bill.bristow@gi.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775-7320
AU: Gonz\'alez, S A
EM: sixto@naic.edu
AF: Arecibo Observatory, HC3 Box 53995, Arecibo, PR 00612
AB: In this paper we describe recent experiments and techniques that push the boundary in terms of the information that can be extracted from the incoherent scatter (IS) spectrum, as well as an application of the Arecibo dual-beam system. One particular problem of the IS radar technique since its beginning has been measuring unambiguously the electron and ion temperature (Te and Ti) plus the molecular ion fraction in the F1 region during the day when Te is greater than Ti. So far, pretty much all IS radars make some assumptions in order to routinely process IS autocorrelation functions to get at least some values for temperatures or ion composition. In this paper we show one solution to this problem, which is based in the combination of plasma line and ion line portions of the IS spectrum to obtain unambiguous Te, Ti and molecular ion fraction during the day. During the nighttime, we cannot measure the plasma line and the F1 region is pretty much gone, but layers typically form at Arecibo in the E region ionosphere. Some of these layers can be very narrow in height and contain metallic ions, and we have in recent times performed spectral measurements with a very high altitude resolution (75 meters), to determine the ion composition within these thin layers. Another interesting recent result that we will discuss is related to the observations of photoelectron enhancement of the incoherent scatter gyrolines at dawn. These new observations at Arecibo confirm the photoelectron enhancement effect of the gyrolines previously observed by the EISCAT VHF radar. Finally, we will show a big improvement in the time resolution of Arecibo ion vector velocity measurements. Until recently, vector velocity measurements (2D or 3D) could only be done by physically rotating the antenna beam to point into different directions, but now we can take advantage of the dual-beam system to determine instantaneously the eastward electric field and the meridional neutral wind velocity in the F region with a time resolution of about one minute.
DE: 2419 Ion chemistry and composition (0335)
DE: 2467 Plasma temperature and density
DE: 2494 Instruments and techniques
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting