TY - JOUR

T1 - A simulation study on the mode conversion process from slow Z-mode to LO mode by the tunneling effect and variations of beaming angle

AU - Kalaee, Mohammad Javad

AU - Katoh, Yuto

N1 - Funding Information:
The authors would like to acknowledge the financial support of University of Tehran for research under grant number 28905/1/02 .
Publisher Copyright:
© 2014 COSPAR. Published by Elsevier Ltd. All rights reserved.

PY - 2014/12/1

Y1 - 2014/12/1

N2 - For a particular angle of incidence wave, it is possible for a slow Z-mode wave incident on an inhomogeneous plasma slab to be converted into an LO mode wave. But for another wave normal angle of the incident wave, it has been considered impossible, since an evanescence region exists between two mode branches. In this case we expect that the mode conversion takes place through the tunneling effect. We investigate the effect of the spatial scale of the density gradient on the mode conversion efficiency in an inhomogeneous plasma where the mode conversion can occur only by the tunneling effect. We use the computer simulation solving Maxwell's equations and the motion of a cold electron fluid. By considering the steepness of the density gradient, the simulation results show the efficient mode conversion could be expected even in the case that the mismatch of the refractive indexes prevents the close coupling of plasma waves. Also, we show for these cases the beaming angle does not correspond to Jones' formula. This effect leads to the angles larger and smaller than the angle estimated by the formula. This type of mode conversion process becomes important in a case where the different plasmas form a discontinuity at their contact boundary.

AB - For a particular angle of incidence wave, it is possible for a slow Z-mode wave incident on an inhomogeneous plasma slab to be converted into an LO mode wave. But for another wave normal angle of the incident wave, it has been considered impossible, since an evanescence region exists between two mode branches. In this case we expect that the mode conversion takes place through the tunneling effect. We investigate the effect of the spatial scale of the density gradient on the mode conversion efficiency in an inhomogeneous plasma where the mode conversion can occur only by the tunneling effect. We use the computer simulation solving Maxwell's equations and the motion of a cold electron fluid. By considering the steepness of the density gradient, the simulation results show the efficient mode conversion could be expected even in the case that the mismatch of the refractive indexes prevents the close coupling of plasma waves. Also, we show for these cases the beaming angle does not correspond to Jones' formula. This effect leads to the angles larger and smaller than the angle estimated by the formula. This type of mode conversion process becomes important in a case where the different plasmas form a discontinuity at their contact boundary.

KW - Density gradient

KW - LO mode

KW - Mode conversion

KW - Tunneling effect

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U2 - 10.1016/j.asr.2014.08.025

DO - 10.1016/j.asr.2014.08.025

M3 - Article

AN - SCOPUS:84922576228

SN - 0273-1177

VL - 54

SP - 2218

EP - 2223

JO - Advances in Space Research

JF - Advances in Space Research

IS - 11

ER -