Coordinated study of subkilometer and 3-m irregularities in the F region generated by high-power HF heating at Arecibo

Journal Article · Tue Nov 01 04:00:00 EST 1983 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA088iA11p09217· OSTI ID:5123535

Basu, S; Ganguly, S; Gordon, W E

High-power high-frequency transmitters near Arecibo were used to generate artificial ionospheric irregularities in the F region. Radio star scintillation observations at 430 MHz were performed at Arecibo Ionospheric Observatory with the 305-m antenna, and radar backscatter measurements at 50 MHz were simultaneously made from Guadeloupe Island to probe the subkilometer and 3-m irregularities in the heated volume. Scintillation studies indicate a low-frequency modulation of the faster intensity fluctuation structure. By the use of plasma drift data this low-frequency modulation of the faster intensity fluctuation structure. By the use of plasma drift data this low-frequency temporal structure translates to spatial dimensions of 1--2 km. The frequency of the modulation envelope is found to be controlled by the heater power and is related to the dominant irregularity wavelength generated by the self-focusing instability. Scintillation spectra imply a steep power law index of approx.5 in the scale length range of about 300 m to 150 m and a shallow index of approx.2 at less than 150 m. The steep power law index may arise from a aperture averaging effect of the large 305-m antenna at Arecibo. Simultaneous measurements of 430-MHz scintillations and 50-MHz radar backscatter from field-aligned striations were performed to show that subkilometer irregularities can be generated by both O and X mode heating whereas the 3-m irregularities are excited only by the O mode heating, as is predicted by the theories of self-focusing and parametric instability.

• Research Organization: Emmanuel College
• OSTI ID: 5123535
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 88:A11; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DISTURBANCES
EARTH ATMOSPHERE
ELECTRON DENSITY
F REGION
INSTABILITY
IONOSPHERE
IONOSPHERIC STORMS
PLANETARY IONOSPHERES
PLASMA DENSITY
PLASMA DRIFT
PLASMA INSTABILITY
SUDDEN IONOSPHERIC DISTURBANCE