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A study of VLF wave propagation characteristics in the earth-ionosphere waveguide

Earth, Planets and Space volume 60, pages 737–741 (2008)Cite this article

Abstract

In the light of newly found applications for very low frequency (VLF) (3–30 kHz) measurements in the prediction of earthquakes and the detection of lightning discharges and gamma ray bursts, there has been a revival of interest in the study of VLF propagation in the earth-ionosphere waveguide. The propagation characteristics of VLF radiowaves in the earth-ionosphere waveguide critically depend upon the lower ionospheric ionization, which determines the conductivity profile of the upper boundary of the waveguide. In this context, it is potentially worthwhile to revisit the waveguide mode analysis to compute propagation parameters of long-distance VLF transmissions while taking into account different approximations to the ionospheric conductivity. We have carried out a waveguide mode analysis of 16-kHz VLF waves traveling great distances, assuming three different models for conductivity. The computational results show that at heights of less than 70 km, the change in the phase of the VLF waves due to changes in phase velocity is smaller when the ionosphere is sharply bound and assumed to have finite conductivity rather than infinite conductivity. The effect of a non-sharp or diffuse boundary at the top of the earth-ionosphere waveguide is found to cause a lowering of the height of reflection.

References

  • Chakrabarti, S., S. Sasmal, M. Saha, R. Khan, D. Bhoumik, and S. K. Chakrabarti, Unusual behavior of D-region ionization time at 18.2 kHz during seismically active days, Indian J. Phys., 81, 531–538, 2007.

    Google Scholar 

  • Chilton, C. J., D. D. Crobie, and A. G. Jean, Phase variations in VLF propagation, in Propagation of radiowaves at frequencies 300 kc/s, edited by Blackband, 257–290, Pergamon Press, London, 1964.

    Google Scholar 

  • Cummer, S. A., Modeling electromagnetic propagation in the earth-ionosphere waveguide, IEEE Trans. Antennas Propagat., 48, 1420–1429, 2000.

    Article  Google Scholar 

  • De, S. S., D. K. De, A. Guha, and P. K. Mandal, Detection of 2004 Leonid meteor shower by observing its effects on VLF transmission, Indian Radio Space Phys., 35, 396–400, 2006.

    Google Scholar 

  • Grubor, D., D. Sulic, and V. Zigman, Influence of solar X-ray flares on the earth-ionosphere waveguide, Serb. Astron. J., 171, 29–35, 2005.

    Article  Google Scholar 

  • Inan, U. S., A. Slingeland, V. P. Pasko, and J. V. Rodriguez, VLF and LF signatures of mesospheric and ionospheric response to lightning discharges, J. Geophys. Res., 101, 5219–5229, 1996.

    Article  Google Scholar 

  • Khan, I., Y. V. P. K. Raghava, and D. N. Madhusudhana Rao, Seasonal variation of diurnal shift in the height of reflection of 16 kHz VLF signals recorded at Visakhapatnam, Proc. A. P. Akad. Sci., 5, 215–219, 2001.

    Google Scholar 

  • Kikuchi, T., Waveguide model analyses of Omega VLF wave propagation at 13.6 kHz, J. Atmos. Terr. Phys., 48, 15–23, 1986.

    Article  Google Scholar 

  • Otsuyama, T., T. Kariya, and M. Hayakawa, VLF signatures of ionospheric perturbations associated with winter lightning in the Hokuriku area of Japan, Adv. Polar Upper Atmos. Res., 17, 109–119, 2003.

    Google Scholar 

  • Reznikov, A. E., A. I. Sukhorukov, D. E. Edemskii, V. V. Kopeikin, P. A. Morozov, B. S. Ryabov, A. Yu. Shchekotov, and V. V. Solov’ev, Investigations of the lower ionosphere over Antarctica via ELF-VLF radiowaves, Antarctic Sci., 5, 107–113, 1993.

    Article  Google Scholar 

  • Singh, B., V. Kushwah, V. Singh, and M. Tomar, Simultaneous ULF/VLF amplitude anomalies observed during moderate earthquakes in Indian region, Indian Radio Space Phys., 34, 221–232, 2005.

    Google Scholar 

  • Wait, J. R., Diurnal change of ionospheric heights deduced from phase velocity measurements at VLF, Proc. IRE, 47, 998, 1959.

    Google Scholar 

  • Wait, J. R., Influence of lower ionosphere on propagation of VLF waves to great distances, J. Res. NBS, 67D, 375–381, 1963.

    Google Scholar 

  • Wait, J. R., Electromagnetic waves in stratified media (2nd Edition), Pergmon Press, Oxford, 1970.

    Google Scholar 

Download references

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Authors and Affiliations

  1. Department of Physics, Andhra University, Visakhapatnam, 530 003, A. P., India

    M. Indira Devi & D. N. Madhusudhana Rao

  2. Department of Instrumentation Technology, College of Engineering, Andhra University, Visakhapatnam, 530 003, A. P., India

    I. Khan

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  1. M. Indira Devi
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  2. I. Khan
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  3. D. N. Madhusudhana Rao
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Correspondence to M. Indira Devi.

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Indira Devi, M., Khan, I. & Madhusudhana Rao, D.N. A study of VLF wave propagation characteristics in the earth-ionosphere waveguide. Earth Planet Sp 60, 737–741 (2008). https://doi.org/10.1186/BF03352822

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  • DOI: https://doi.org/10.1186/BF03352822

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