Skip to main content

A computer simulation study on the mode conversion process from slow X-mode to fast X-mode by the tunneling effect


The mode conversion process from slow X-mode waves to fast X-mode waves by the tunneling effect has been studied by means of computer simulation. On the basis of the new approach by the simulation, we have confirmed that the mode conversion to the fast X-mode waves is especially effective in the case where the width of the evanescent layer which exists between the local UHR frequency and the local fast X-mode cut-off frequency, is of the order of the wave length of the incident slow X-mode waves. In space plasmas, this type of mode conversion process becomes important for the case where the different plasmas form a sharp boundary or a discontinuity at their contact boundary with a scale size of the order of the wave length of the incident slow X-mode waves.


  • Budden, K. G., The non-existence of a “fourth reflection condition” for radio waves in the ionosphere, in Physics of the Ionosphere: Report of Phys. Soc. Conf. Cavendish Lab., p. 320, Physical Society, London, 1955.

    Google Scholar 

  • Budden, K. G., The theory of radio windows in the ionosphere and magnetosphere, J. Atmos. Terr. Phys., 42, 287–298, 1980.

    Article  Google Scholar 

  • Jones, D., Mode-coupling of Z-mode waves as a source of terrestrial kilo-metric and Jovian decametric radiations, Astron. Astrophys., 55, 245–252, 1977.

    Google Scholar 

  • Omura, Y. and J. L. Green, Plasma wave signatures in the magnetotail reconnection region: MHD simulation and ray tracing, J. Geophys. Res., 98(A6), 9189–9199, 1993.

    Article  Google Scholar 

  • Oya, H., Conversion of electrostatic plasma waves into electromagnetic waves: numerical calculation of the dispersion relation for all wavelengths, Radio Sci., 6, 1131–1141, 1971.

    Article  Google Scholar 

  • Oya, H., Studies on plasma and plasma waves in the plasmasphere and auroral particle acceleration region, by PWS on board the EXOS-D (Akebono) satellite, J. Geomag. Geoelectr., 43, 369–393, 1991.

    Article  Google Scholar 

  • Roux, A. and R. Pellat, Coherent generation of the terrestrial kilometric radiation by nonlinear beating of electrostatic waves, J. Geophys. Res., 84, 5189–5198, 1979.

    Article  Google Scholar 

  • Sato, M., Studies on kilometric radiations associated with plasmasphere disturbances-relation to the “donkey ear” shape plasmasphere, Ph.D. thesis, Tohoku University, Japan, 2001.

    Google Scholar 

  • Stix, T. H., Waves in Plasmas, Am. Inst. of Phys., New York, 1992.

    Google Scholar 

  • Tang, T. W., Mode conversion in a weakly inhomogeneous collisionless magnetoplasma, Phys. Fluids, 13(1), 121–135, 1970.

    Article  Google Scholar 

  • Wu, C. S. and L. C. Lee, A theory of the terrestrial kilometric radiation, Astrophys. J., 230, 621–626, 1979.

    Article  Google Scholar 

Download references

Author information



Corresponding author

Correspondence to Yuto Katoh.

Rights and permissions

Open Access  This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.

The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

To view a copy of this licence, visit

Reprints and Permissions

About this article

Cite this article

Katoh, Y., Iizima, M. A computer simulation study on the mode conversion process from slow X-mode to fast X-mode by the tunneling effect. Earth Planet Sp 58, e53–e56 (2006).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

Key words

  • Mode conversion
  • numerical experiment