Analytical Approach to Calculate Quasi-thermal Noise Spectrum in Irregular Plasma |
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| Authors: | Nikolay A Zabotin Andrey G Bronin Yury V Chugunov Evgene A Mareev |
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| Institution: | (1) Rostov State University, Rostov-on-Don, Russia;(2) Institute of Applied Physics RAS, Nizhni Novgorod, Russia |
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| Abstract: | Basic properties of quasi-thermal noise spectrum in irregular plasma have been investigated using an analytical point of view.
A simple formula for the plasma frequency splitting effect has been obtained for ionospheric conditions. A passive electric
antenna, immersed in a stable plasma, detects the fluctuations of the electric potential due to thermal motion of the ambient
particles. Properties of this quasi-thermal noise spectrum in homogeneous plasma are relatively well known and are effectively
used for diagnostics of space plasma (Aksenov et al., 1978; Trakhtengerts and Chugunov, 1978; Kellog, 1981; Meyer-Vernet and Perche, 1989). Especially, in the Earth's ionosphere
or solar wind plasma, random irregularities of electron density are always present. These irregularities may substantially
change properties of these media through electromagnetic radiation and may also modify quasi-thermal noise spectrum, which
depends on the effective dielectric permittivity tensor. This tensor is defined as the dielectric permittivity tensor of some
imaginary `effective' regular medium in which the field of point source is the same as the mean field in the medium with random
irregularities (Ryzhov, Tamoikin and Tatarskii, 1965; Ryzhov 1968). Since the correlation function of electric field fluctuations
in random medium may be expressed through the effective dielectric constant tensor (Ryzhov, 1968), it may be used for direct
calculation of quasi-thermal noise spectrum. In Zabotin et al. (2000), the Born approximation was used to calculate numerically
the effective dielectric permittivity tensor and the modified noise spectrum while we analytically estimate herein the modified
noise spectrum.
This revised version was published online in July 2006 with corrections to the Cover Date. |
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