Temporal evolution of the HF-enhanced plasma line in sporadic E

Journal Article · Fri Jan 01 00:00:00 EST 1988 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA093iA01p00196· OSTI ID:6092405

Djuth, F T ^[1]; Gonzales, C A ^[2]

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1. Aerospace Corp., Los Angeles, CA (United States)
2. Arecibo Observatory (Puerto Rico)

The high-power, high-frequency (HF) facility at Arecibo, Puerto Rico, has been used to study the excitation of Langmuir waves in mid-latitude sporadic E. Measurements of the temporal evolution of so-called HF-enhanced plasma line (HFPL) were made using the Arecibo 430-MHz radar. After HF turn-on in the plasma the HFPL exhibits a rapid growth phase followed by a quick overshoot. During periods of strong HFPL excitation the e-folding growth time of the HFPL power is typically {approx lt}20 {mu}s, and the total overshoot period is {approximately}1 ms. On the basis of the current observations, mode conversion of the HF wave into Langmuir waves near HF reflection appears to be a promising mechanism for the production of Langmuir waves in sporadic E. Caviton formation at the critical layer is expected to accompany this process, and there is some evidence that the 430-MHz radar is probing the plasma in a region where density cavities of this nature form. While no specific explanation is offered for the HFPL overshoot, it appears that this phenomenon is fundamental to the Langmuir wave excitation process.

• OSTI ID: 6092405
• Journal Information: Journal of Geophysical Research; (United States), Vol. 93:A1; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
SPORADIC E
PLASMA WAVES
EXCITATION
EXPERIMENTAL DATA
IONOSPHERE
MODIFICATIONS
PLASMA DENSITY
RADAR
RADIOWAVE RADIATION
REFLECTION
TWO-STREAM INSTABILITY
WAVE PROPAGATION
DATA
E REGION
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
ENERGY-LEVEL TRANSITIONS
INFORMATION
INSTABILITY
MEASURING INSTRUMENTS
NUMERICAL DATA
PLANETARY IONOSPHERES
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
RADIATIONS
RANGE FINDERS
661320* - Auroral
Ionospheric
& Magnetospheric Phenomena- (1992-)