- Article
- Open access
- Published:
Generation mechanism of Z-mode waves in the equatorial plasmasphere
Earth, Planets and Space volume 59, pages 1027–1034 (2007)
Abstract
In order to clarify the generation mechanism of Z-mode waves observed in the equatorial plasmasphere, the growth rate of Z-mode electromagnetic waves has been calculated under the higher-order cyclotron interaction process. Z-mode waves can interact with some tens of keV electrons with large pitch angles even in the dense cold background, and the amplitude is consistent with the Akebono plasma wave measurements. UHR and whistler mode waves are also excited by the same electron distribution, and this is also consistent with observations. The origin of these energetic electrons are identified as the ring current electrons injected into the plasmasphere by the intense large-scale electric field during geomagnetic storms, accelerated perpendicular to the ambient magnetic field and confined around the geomagnetic equator conserving the first and second adiabatic invariants. Since the intensity of Z-mode and UHR waves is associated with the development and decay of the ring current, ring current particles are most possible candidate for the free energy source of these waves.
References
Baldwin, D. E., I. B. Bernstein, and M. P. H. Weenink, Kinetic theory of plasma waves in a magnetic field, in Advances in plasma physics, edited by A. Simon and W. B. Thompson, vol. 3, pp. 1–125, Interscience Publishers, 1969.
Bauer, S. J. and R. G. Stone, Satellite Observations of Radio Noise in the Magnetosphere, Nature, 218, 1145, 1968.
Burke, W. J., N. C. Maynard, M. P. Hagan, R. A. Wolf, G. R. Wilson, L. C. Gentile, M. S. Gussenhoven, C. Y. Huang, T. W. Garner, and F. J. Rich, Electrodynamics of the inner magnetosphere observed in the dusk sector by CRRES and DMSP during the magnetic storm of June 4–6, 1991, J. Geophys. Res., 103, 29,399–29,418, 1998.
Calvert, W., Oblique z-Mode Echoes in the Topside Ionosphere, J. Geophys. Res., 71, 5579, 1966.
Christiansen, P. J., M. P. Gough, G. Martelli, J. J. Bloch, N. Cornilleau, J. Etcheto, R. Gendrin, and C. Beghin, GEOS-1 observations of electrostatic waves, and their relationship with plasma parameters, Space Sci. Rev., 22, 383–400, 1978.
Eckersley, T. L., Discussion on the Ionosphere, Proc. Roy. Soc., A, 141, 710, 1933.
Gregory, P. C., Radio emission from auroral electrons, Nature, 221, 350, 1969.
Harvey, C. C., Radio emission from geomagnetically trapped particles, Nature, 217, 50–51, 1968.
Horita, R. E. and H. G. James, Two-point studies of fast Z-mode waves with dipoles in the ionosphere, Radio Sci., 39, 4001, 2004.
Jones, D., Latitudinal beaming of planetary radio emissions, Nature, 288, 225–229, 1980.
Katoh, Y. and Y. Omura, Computer simulation of chorus wave generation in the Earth’s inner magnetosphere, Geophys. Res. Lett., 34, 3102, 2007.
Kennel, C. F. and H. E. Petscheck, Limit on stably trapped particle fluxes, J. Geophys. Res., 71, 1–28, 1966.
Kutiev, I., K. Oyama, and T. Abe, Analytical representation of the plasmasphere electron temperature distribution based on Akebono data, J. Geophys. Res., 107, SMP 24–1, 2002.
Lee, L. C., C. S. Wu, H. P. Freund, D. Dillenburg, and J. Goedert, Excitation of high-frequency waves with mixed polarization by streaming energetic electrons, J. Plasma Phys., 22, 277–288, 1979.
Maynard, N. C., W. J. Burke, E. M. Basinska, G. M. Erickson, W. J. Hughes, H. J. Singer, A. G. Yahnin, D. A. Hardy, and F. S. Mozer, Dynamics of the inner magnetosphere near times of substorm onsets, J. Geophys. Res., 101, 7705–7736, 1996.
Melrose, D. B., G. A. Dulk, and R. G. Hewitt, Electron-cyclotron maser emission—Relative growth and damping rates for different modes and harmonics, J. Geophys. Res., 89, 897–904, 1984.
Mishin, E. V. and W. J. Burke, Stormtime coupling of the ring current, plasmasphere, and topside ionosphere: Electromagnetic and plasma disturbances, J. Geophys. Res., 110, 7209, 2005.
Mosier, S., M. Kaiser, and L. Brown, Observations of noise bands associated with the upper hybrid resonance by the Imp 6 radio astronomy experiment, J. Geophys. Res., 10, 1673–1979, 1973.
Nishimura, Y., T. Ono, M. Iizima, A. Shinbori, A. Kumamoto, and H. Oya, Statistical studies of fast and slow Z-mode plasma waves in and beyond the equatorial plasmasphere based on long-term Akebono observations, Earth Planets Space, 58, 343–346, 2006.
Nishimura, Y., A. Shinbori, T. Ono, M. Iizima, and A. Kumamoto, Evolution of ring current and radiation belt particles under the influence of storm-time electric fields, J. Geophys. Res., 2007 (in press).
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. Suppl., 43, 369–393, 1991.
Oya, H., A. Morioka, K. Kobayashi, M. Iizima, T. Ono, H. Miyaoka, T. Okada, and T. Obara, Plasma wave observation and sounder experiments (PWS) using the Akebono (EXOS-D) satellite—Instrumentation and initial results including discovery of the high altitude equatorial plasma turbulence, J. Geomag. Geoelectr., 42, 411–442, 1990.
Oya, H., M. Iizima, and A. Morioka, Plasma turbulence disc circulating the equatorial region of the plasmasphere identified by the plasma wave detector (PWS) onboard the Akebono (EXOS-D) satellite, Geophys. Res. Lett., 18, 329–332, 1991.
Roederer, J. G., Dynamics of Geomagnetically Trapped Radiation, in Physics and Chemistry in Space, edited by J. G. Roederer, Denver and J. Zähringer, vol. 2, Springer-Verlag, 1970.
Winglee, R. M. and G. A. Dulk, The electron-cyclotron maser instability as a source of plasma radiation, Ap. J., 307, 808–819, 1986.
Wu, C. S. and L. C. Lee, A theory of the terrestrial kilometric radiation, Ap. J., 230, 621–626, 1979.
Wygant, J., D. Rowland, H. J. Singer, M. Temerin, F. Mozer, and M. K. Hudson, Experimental evidence on the role of the large spatial scale electric field in creating the ring current, J. Geophys. Res., 103, 29,527–29,544, 1998.
Yoon, P. H., A. T. Weatherwax, and T. J. Rosenberg, On the generation of auroral radio emissions at harmonics of the lower ionospheric electron cyclotron frequency: X, O and Z mode maser calculations, J. Geophys. Res., 103, 4071–4078, 1998.
Author information
Authors and Affiliations
Corresponding author
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 https://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
Nishimura, Y., Ono, T., Iizima, M. et al. Generation mechanism of Z-mode waves in the equatorial plasmasphere. Earth Planet Sp 59, 1027–1034 (2007). https://doi.org/10.1186/BF03352043
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1186/BF03352043