Dipole Measurements of Waves in the Ionosphere

  • H.G. James
Part of the Lecture Notes in Physics book series (LNP, volume 687)

Abstract

The theory of distributed dipole antennas in magnetoplasmas has been tested through the analysis of the data from the two-point propagation experiment OEDIPUS C (OC). The transmission of electromagnetic signals over a 1-km distance in the ionosphere has been used to substantiate the theory of emission, propagation and detection of waves in a cold magnetoplasma. Confirmations and insights about the dipole theory arising from the OC research results have occasioned a return to some older data that can be profitably interpreted with them. The concept of dipole effective length Leff has been re-examined quantitatively with the help of the reciprocity principle. It is found that previous measurements of electromagnetic whistler-mode propagation give Leff values similar to those predicted using a classic reciprocity definition brought over from the vacuum dipole theory. In contrast, OC investigations found that Leff can be many times the dipole physical length for propagation near the whistler-mode resonance cone. The finding has important consequences for the interpretation of the measured strength of the radio emission auroral hiss and, by extension, the nature of its source. Since intra-ionospheric experiments on propagation near either the lower- or the upper-oblique-resonance cone produced extremely strong transmission, the Leff applied to the interpretation of the strength of plasma-wave phenomena in the corresponding frequency domains must be chosen with care.

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References

  1. [1]
    Bell, T.F., R.A. Helliwell and M.K. Hudson: Lower hybrid waves excited through linear mode coupling and the heating of ions in the auroral and subauroral magnetosphere, J. Geophys. Res. 96, 11,379–11,388 (1991). Google Scholar
  2. [2]
    Benson, R.F., P.A. Webb, J.L. Green, D.L. Carpenter, V.S. Sonwalkar, H.G. James and B.W. Reinisch: Active wave experiments in space plasmas: the Z mode. In: Proceedings Volume for the Ringberg Workshop, edited by J. LaBelle and R. A. Treumann, Springer Lecture Notes in Physics, Springer New York-Heidelberg (2005). Google Scholar
  3. [3]
    Chugunov, Yu.V.: Receiving antenna in a magnetoplasma in the resonance frequency band, Radiophys. Quantum Electron. 44, 151–160 (2001). Google Scholar
  4. [4]
    Chugunov, Yu.V., E.A. Mareev, V. Fiala and H.G. James: Transmission of waves near the lower oblique resonance using dipoles in the ionosphere, Radio Sci. 38, 1022, doi:10.1029/2001RS002531 (2003). Google Scholar
  5. [5]
    Ergun, R.E., C.W. Carlson, J.P. McFadden, F.S. Mozer, L. Muschietti, I. Roth and R.J. Strangeway: Debye-scale plasma structures associated with magnetic-field-aligned fields, Phys. Rev. Lett. 81, 826–829 (1998). Google Scholar
  6. [6]
    Gurnett, D.A. and L.A. Frank: VLF hiss and related plasma observations in the polar magnetosphere, J. Geophys. Res. 77, 172–190 (1972). Google Scholar
  7. [7]
    Horita, R.E. and H.G. James: Two point studies of fast Z mode waves with dipoles in the ionosphere, Radio Sci. 39, doi:10.1029/2003RS002994 (2004). Google Scholar
  8. [8]
    Imachi, T., I. Nagano, S. Yagitani, M. Tsutsui and H. Matsumoto: E.ective lengths of the dipole antennas aboard Geotail spacecraft. In: Proc. 2000 Int. Sympos. Antennas and Propagat, (ISAP2000), IEICE of Japan, Tokyo 819- 822 (2000). Google Scholar
  9. [9]
    James, H.G.: Whistler-mode hiss at low and medium frequencies in the daysidecusp ionosphere, J. Geophys. Res. 78, 4578–4599 (1973). Google Scholar
  10. [10]
    James, H.G.: Wave propagation experiments at medium frequencies between two ionospheric satellites, 2, Whistler-Mode pulses, Radio Sci. 13, 543–558 (1978). Google Scholar
  11. [11]
    James, H.G.: Wave propagation experiments at medium frequencies between two ionospheric satellites, 3, Z mode pulses, J. Geophys. Res. 84, 499–506 (1979). Google Scholar
  12. [12]
    James, H.G.: Electrostatic resonance-cone waves emitted by a dipole in the ionosphere, IEEE Trans. Antennas Propagat. 48, 1340–1348 (2000). Google Scholar
  13. [13]
    James, H.G.: Electromagnetic whistler-mode radiation from a dipole in the ionosphere, Radio Sci. 38, 1009, doi:10.1029/2002RS002609 (2003). Google Scholar
  14. [14]
    James, H.G.: Slow Z-mode radiation from sounder-accelerated electrons, J. Atmos. Solar-Terr. Phys. 66, 1755–1765 (2004). Google Scholar
  15. [15]
    James, H.G. and W. Calvert: Interference fringes detected by OEDIPUS C, Radio Sci. 33, 617–629 (1998). Google Scholar
  16. [16]
    Jordan, E.C.: Electromagnetic Waves and Radiating Systems, Prentice-Hall, Englewood Cliffs NJ (1950). Google Scholar
  17. [17]
    Jørgensen, T.S.: Interpretation of auroral hiss measured on POGO-2 and at Byrd Station in terms of incoherent Cerenkov radiation, J. Geophys. Res. 73, 1055–1069 (1968). Google Scholar
  18. [18]
    Kuehl, H.H.: Electromagnetic radiation from an electric dipole in a cold anisotropic plasma, Phys. Fluids 5, 1095–1103 (1962). Google Scholar
  19. [19]
    LaBelle, J. and R.A. Treumann: Auroral radio emissions, 1. Hisses, roars and bursts, Space Sci. Rev. 101, 295–440 (2002). Google Scholar
  20. [20]
    Lim, T.L. and T. Laaspere: An evaluation of the intensity of Cerenkov radiation from auroral electrons with energies down to 100 eV, J, Geophys. Res. 77, 4145- 4157 (1972). Google Scholar
  21. [21]
    Maeda, K.: A calculation of auroral hiss with improved models for geoplasma and magnetic field, Planet. Space. Sci. 23:843–865 (1975). Google Scholar
  22. [22]
    Mareev, E.A. and Yu.V. Chugunov: Excitation of plasma resonance in a magnetoactive plasma by external source, 1, A source in a homogeneous plasma, Radiophys. Quantum Electron. 30, 713–718 (1987). Google Scholar
  23. [23]
    Mosier, S.R. and D.A. Gurnett: Observed correlations betwen auroral and VLF emissions, J. Geophys. Res. 77, 1137–1145 (1972). Google Scholar
  24. [24]
    Paschmann, G., S. Haaland and R.A. Treumann: Auroral plasma physics, Space Sci. Rev. 103, No. 1–4 (2002). Google Scholar
  25. [25]
    Sonwalkar, V.S.: The influence of plasma density irregularities on whistler mode wave propagation. In: Proceedings Volume for the Ringberg Workshop, edited by J. LaBelle and R. A. Treumann, Springer Lecture Notes in Physics, Springer New York-Heidelberg (2005). Google Scholar
  26. [26]
    Sonwalkar, V.S. and U.S. Inan: Measurements of Siple transmitter signals on the DE 1 satellite: wave normal direction and antenna effective length, J. Geophys. Res. 91, 154–164 (1986). Google Scholar
  27. [27]
    Sonwalkar, V.S., D.L. Carpenter, T.F. Bell, M. Spasojevic, U.S. Inan, J. Li, X. Chen, A. Venkatasubramanian, J. Harikumar, R.F. Benson, W.W.L. Taylor and B.W. Reinisch: Diagnostics of magnetospheric electron density and irregularities at altitudes <5000 km using whistler and Z mode echoes from radio sounding on the IMAGE satellite, J. Geophys. Res. 109, A11212, doi:10.1029/2004JA010471 (2004). Google Scholar
  28. [28]
    Stix, T.H.: Waves in Plasmas, American Institute of Physics, New York (1992). Google Scholar
  29. [29]
    Taylor, W.W.L. and S.D. Shawhan: A test of incoherent Cerenkov radiation for VLF hiss and other magnetospheric emissions, J. Geophys. Res. 79, 105–117 (1974). Google Scholar
  30. [30]
    Wang, T.N.C. and T.F. Bell: VLF/ELF radiation patterns of arbitrarily oriented electric and magnetic dipoles in a cold lossless multicomponent magnetosplasma, J. Geophys. Res. 77, 1174–1189 (1972). Google Scholar

Copyright information

© Springer 2006

Authors and Affiliations

  • H.G. James
    • 1
  1. 1.Communications Research Centre CanadaOttawa, OntarioCanada

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