HR: 0800h
AN: SA21C-0376    [Abstracts]
TI: Role of Cavitons in Electromagnetic Wave Interactions with Ionospheric plasmas
AU: * Wong, A Y
EM: awong@physics.ucla.edu
AF: UCLA Plasma Physics Laboratory, 405 Hilgard Ave., Los Angeles, CA 90095-9000 United States
AU: * Wong, A Y
EM: awong@physics.ucla.edu
AF: UCLA-HIPAS Observatory, 7795 Chena Hot Springs Road, Fairbanks, AK 99712 United States
AU: Pau, J
EM: pau@physics.ucla.edu
AF: IFSHE, Box 951547, Los Angeles, CA 90095-1547 United States
AU: Dickman, R
EM: rdickman@hipas.alaska.edu
AF: UCLA Plasma Physics Laboratory, 405 Hilgard Ave., Los Angeles, CA 90095-9000 United States
AU: Dickman, R
EM: rdickman@hipas.alaska.edu
AF: UCLA-HIPAS Observatory, 7795 Chena Hot Springs Road, Fairbanks, AK 99712 United States
AU: Beam, B
AF: IFSHE, Box 951547, Los Angeles, CA 90095-1547 United States
AU: Wang, W
EM: weiyuan@hipas.alaska.edu
AF: IFSHE, Box 951547, Los Angeles, CA 90095-1547 United States
AU: Hicks, N
EM: hicks@physics.ucla.edu
AF: UCLA Plasma Physics Laboratory, 405 Hilgard Ave., Los Angeles, CA 90095-9000 United States
AU: Hicks, N
EM: hicks@physics.ucla.edu
AF: UCLA-HIPAS Observatory, 7795 Chena Hot Springs Road, Fairbanks, AK 99712 United States
AU: Rosenthal, G
EM: grosenthal@physics.ucla.edu
AF: UCLA Plasma Physics Laboratory, 405 Hilgard Ave., Los Angeles, CA 90095-9000 United States
AU: Rosenthal, G
EM: grosenthal@physics.ucla.edu
AF: UCLA-HIPAS Observatory, 7795 Chena Hot Springs Road, Fairbanks, AK 99712 United States
AU: Quon, B
EM: bquon1@msn.com
AF: IFSHE, Box 951547, Los Angeles, CA 90095-1547 United States
AB: Cavitons, nonlinear density cavities created by localized enhanced electric fields, can explain the lowering of thresholds in parametric instabilities, the trapping of waves, accelerated electrons and optical emission. With the support of laboratory observations and computer modeling, it is postulated that energetic electrons are produced in density cavities or field-aligned density striations. Experimentally it is optimal to steer the EM wave along the earth's magnetic field ({\bf B}) to cause conversion of EM waves to localized ES waves that are trapped inside cavitons [Wong et al., 1981]. Electrons are accelerated by series of cavitons both along and across the earth's magnetic field. We will demonstrate that electrons are efficiently accelerated at the second harmonic of the electron cyclotron frequency $2f_{ce}$ due to finite larmor radius effects. This finding also explains the requirement of the optimal propagation direction along {\bf B}. Laboratory experiments and computer modeling have demonstrated the acceleration of electrons and ions by self-consistent enhanced ES fields. Optical, SEE and EM measurements of polarization in field experiments are presented to support our picture of cavitons responsible for such accelerations. Our model predicts strong elliptical polarization of electric fields with axes both parallel to and perpendicular to B in the waves reflected from the critical layer. Experiments on detection of such polarizations and the lowering of thresholds at frequencies near $2f_{ce}$ will be reported. Wong, A.Y. et al., JGR, 86(A9), pp 7718-32, 1981
DE: 4275 Remote sensing and electromagnetic processes (0689)
DE: 2403 Active experiments
DE: 2407 Auroral ionosphere (2704)
DE: 2439 Ionospheric irregularities
DE: 0310 Airglow and aurora
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting