HF-enhanced plasma lines in the lower ionosphere

Journal Article · Sun Jan 01 04:00:00 EST 1984 · Radio Sci.; (United States)

DOI:https://doi.org/10.1029/RS019i001p00383· OSTI ID:6530261

Djuth, F T

The ionospheric modification facility at Arecibo, Puerto Rico, has been used to study Langmuir waves excited in the lower ionosphere by a high-power HF radio wave. Measurements of HF-enhanced plasma lines have been made in the lower F region (less than 160 km altitude) and in the E region using the 430-MHz radar at Arecibo Observatory. These measurements complement observations made in the past at higher altitudes. Enhanced plasma line spectra observed in the lower F region peak at the so-called 'decay line' and contain additional spectral structure similar to that found in the upper F region. In the E region the spectra exhibit narrow peaks located at 430 MHz + or - f(HF), where f(HF) is the frequency of the modifying HF wave. While strong plasma line enhancements are commonly observed in sporadic E, only weak enhancements have been detected in the normal daytime E layer. Candidate mechanisms for the E region enhancements include the oscillating two-stream instability and direct conversion of the HF wave into Langmuir waves.

• Research Organization: Aerospace Corp., Space Sciences Laboratory, Los Angeles, CA
• OSTI ID: 6530261
• Journal Information: Radio Sci.; (United States), Journal Name: Radio Sci.; (United States) Vol. 19; ISSN RASCA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DAMPING
E REGION
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
F REGION
IONOSPHERE
LANDAU DAMPING
PLANETARY IONOSPHERES
PLASMA WAVES
RADIATIONS
RADIOWAVE RADIATION
WAVE PROPAGATION