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A comparison of the beat method of determining low electron densities from topside ionograms with the plasma‐frequency resonance method
Author(s) -
Whitteker J. H.
Publication year - 1978
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs013i006p01047
Subject(s) - beat (acoustics) , electron density , electron , plasma , resonance (particle physics) , atomic physics , computational physics , plasma oscillation , physics , nuclear magnetic resonance , optics , quantum mechanics
A comparison is made between electron densities derived from the frequency of the plasma resonance and densities derived from the frequency of the beat between the electron gyrofrequency (ƒ H ) and the upper hybrid frequency (ƒ T ), over the density range 150 to 300 cm −3 . Determinations were made from 77 ISIS 2 high‐latitude ionograms on which both methods could be used. Densities derived from the ƒ T −ƒ H beat frequency were found to be lower than those from the plasma‐frequency resonance by an average of 10%, with a dispersion of 10%. Although this result does not apply directly to electron densities of < 100 cm −3 for which the beat method is normally used, it indicates that the method is more accurate than might be supposed from theory applied to higher densities. The result also puts experimental constraints on the frequencies at which the ƒ H and ƒ T resonances occur.