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On VLF Radiation Resistance of an Electric Dipole in a Cold Magnetoplasma
Author(s) -
Wang T. N. C.,
Bell T. F.
Publication year - 1970
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/rs005i003p00605
Subject(s) - dipole , physics , radiation resistance , electric field , magnetosphere , magnetic dipole , radiation , plasma , computational physics , atomic physics , magnetic field , optics , nuclear physics , quantum mechanics
By using full‐wave theory, an analysis is made of the radiation resistance of a short filamentary electric dipole, oriented with an arbitrary angle with respect to the static magnetic field, in a cold, uniform magnetoplasma. The frequency range considered lies below the local lower hybrid resonance frequency and above the proton gyrofrequency, and in this range approximate closed‐form expressions for the radiation resistance are obtained by using a plasma model appropriate to the magnetosphere. These closed‐form expressions are valid for dipoles of moderately restricted length, and the physical implications of this length restriction are discussed. It is found that the radiation resistance R increases rapidly as ф 0 , the angle of dipole orientation with respect to the magnetic field, varies from 0° to 30° but only gradually as ф 0 varies from 30° up to 90°. The ratio of R (ф 0 = 90°)/ R (ф 0 = 0°) is approximately equal to (ƒ He /ƒ) 2 . Except for the case of parallel orientation and ƒ < 10 −2 ƒ He , the radiation resistance of an electric dipole in the magnetoplasma is ∼ 10 2 to 10 5 times larger than that in free space. Thus, for the low frequency range considered, an electric dipole in the magnetoplasma is generally much more efficient that it would be in free space.