Magnetized Plasma with Ferrite Grains as Tunable Anisotropic left Handed Media
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Date
2016-08
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Addis Ababa University
Abstract
Since the report made by Veselago in 1968 about materials with negative refractive
index, and strictly speaking since the experimental realization in 2000 by R. Shelby, et.
al. of artificially constructed materials exhibiting negative index, many investigators
and scholars became interested and devote their time and knowledge in search of
these negative index (NI) materials, either from artificially engineered materials or to
derive them from naturally occurring materials.
This thesis is devoted to the analysis of the electrodynamics and the dispersion
properties of magnetized plasma with ferromagnetic grains (MPFG) in a constant
magnetic field. A magnetized plasma naturally is not transparent to light for some
range of frequency. This range of frequency which the magnetized plasma is not transparent,
obviously, is a range in which the permittivity is negative. So, if, in some way,
we introduce magnetically active materials into the magnetized plasma in such a way
to enhance its magnetic activity we may achieve a magnetic resonance, a dispersion
related with magnetic response of magnetized grains to the variable magnetic field.
The mathematical analysis and the different graphs against the frequency of the wave
show that in a relatively narrow frequency band !M (!M is the ferromagnetic resonance
frequency) both the magnetic permeability and the electric permittivity have
negative value and the MPFG behaves as a NI material. That is, the introduction
of the ferrite grains makes the magnetized plasma transparent to the electromagnetic
wave for the range of frequency where the ordinary plasma is nontransparent. Moreover,
in this range of frequency the phase and group velocity of the electromagnetic
wave are opposite, which is one of the criterion for the left-handed media
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Magnetized Plasma with Ferrite