Cite abstracts as Author(s) (2006), Title, Eos Trans. AGU,
87(52), Fall Meet. Suppl., Abstract xxxxx-xx

HR:  1340h
AN: SA53B-1379
TI: Non-Maxwellian model of ionospheric heating by HF radiation
AU: * Lehtinen, N G
EM: nleht@stanford.edu
AF: STAR Lab, Electrical Engineering, Stanford University, 350 Serra Mall, Stanford, CA 94305 United States
AU: Inan, U S
AF: STAR Lab, Electrical Engineering, Stanford University, 350 Serra Mall, Stanford, CA 94305 United States

AB: Ionospheric DC conductivity changes due to HF (high-frequency)
heating are considered using a kinetic (non- Maxwellian) model. The
modification of the electron distribution caused by propagation and
absorption of ordinary and extraordinary waves are calculated by
taking into account self-absorption due to modification of the
background HF conductivity. The processes considered in the kinetic
equation for electron distribution include excitations of electronic
and vibrational levels of atmospheric molecules, small rotational
losses, ionization and attachment. We consider steady-state and
square-wave modulated heating regimes. Results indicate that lower
modulation frequencies, with the same amplitude of HF field at the
source, lead to higher changes of ionospheric conductivity. The
resultant ELF/VLF wave generation by modulation of the polar
electrojet current is calculated using a finite difference model. The
differences between kinetic (non- Maxwellian) and thermal (Maxwellian)
modelling approaches are discussed. Comparisons indicate that the
assumption of Maxwellian electron distribution leads to
underestimation of electron temperature and concductivity changes.

DE: 2400 IONOSPHERE (6929)
DE: 2403 Active experiments
DE: 2447 Modeling and forecasting
DE: 2487 Wave propagation (0689, 3285, 4275, 4455, 6934)
SC: SPA-Aeronomy [SA]
MN: 2006 Fall Meeting