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Simultaneous observation of HF‐enhanced plasma waves and HF‐wave self‐focusing
Author(s) -
Frey A.,
Duncan L. M.
Publication year - 1984
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl011i007p00677
Subject(s) - scintillation , ionosphere , radio wave , incoherent scatter , radar , wavelength , electron density , physics , high frequency , optics , line of sight , plasma , computational physics , geophysics , astrophysics , telecommunications , quantum mechanics , detector , computer science
Intense HF‐radiowaves of the ordinary mode transmitted from the ground enhance plasma waves near the reflection height. These have been extensively studied in the past by the use of Incoherent‐Scatter‐Radars. Intense HF‐radiowaves propagating in the ionosphere also produce electron density irregularities with scale sizes much larger than the HF wavelength of ∼ 60 m. These have been observed by radio star intensity scintillations. For the past 2 years a new method was used at Arecibo, P.R. which allows radar‐ and scintillation‐measurements at 430 MHz to be performed simultaneously along the same line of sight. The scale sizes deduced from the scintillation measurements are shorter than the scale sizes observed with the radar and are inconsistent with the HF‐power density thresholds predicted by existing theories.