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Simulation of mode conversion from UHR-mode wave to LO-mode wave in an inhomogeneous plasma with different wave normal angles

Earth, Planets and Space volume 61, pages 1243–1254 (2009)Cite this article

Abstract

We have investigated a linear mode conversion process among UHR-mode, Z-mode, and LO-mode waves by a computer simulation solving Maxwell’s equations and the motion of a cold electron fluid. The characteristics of the wave coupling process occurring in the cold magnetized plasma were examined in detail for the case of an inhomogeneity of plasma density lying perpendicular to the ambient magnetic field. The dependence of the conversion efficiency on the incident wave normal angle, wave frequency, background plasma frequency, and steepness of density gradient was studied. The results show that an efficient mode conversion occurred in the conversion process from Z-mode to LO-mode waves rather than from the coupling between UHR-mode to LO-mode waves. They also show that the highest conversion efficiency was obtained under the specific condition of the wave normal angle for the incident waves. In the specific case of such critical wave normal angles, we found that perpendicular components of refractive indexes became zero at the site of mode conversion, which is consistent with previously published results. We also show that the range of the critical normal angle varied depending on both the plasma frequency and the wave frequency. The simulation results also reveal that, when the steepness of the density gradient was taken into consideration, efficient mode conversion could be expected even in the case of the mismatch of the refractive indexes preventing the close coupling of plasma waves.

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Author notes

  1. Masahide Iizima

    Present address: Shukutoku University, Japan

  2. Yukitoshi Nishimura

    Present address: Solar-Terrestrial Environment Laboratory, Nagoya University, Japan

Affiliations

  1. Department of Geophysics, Graduate School of Science, Tohoku University, Japan

    Mohammad Javad Kalaee, Takayuki Ono, Yuto Katoh, Masahide Iizima & Yukitoshi Nishimura

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  1. Mohammad Javad Kalaee
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  2. Takayuki Ono
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  3. Yuto Katoh
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  4. Masahide Iizima
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  5. Yukitoshi Nishimura
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Correspondence to Mohammad Javad Kalaee.

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Kalaee, M.J., Ono, T., Katoh, Y. et al. Simulation of mode conversion from UHR-mode wave to LO-mode wave in an inhomogeneous plasma with different wave normal angles. Earth Planet Sp 61, 1243–1254 (2009). https://doi.org/10.1186/BF03352977

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  • DOI: https://doi.org/10.1186/BF03352977

Key words

  • Mode conversion
  • numerical simulation
  • LO-mode
  • wave generation process