scholarly journals AN APPLICATION OF MICROWAVES REFRACTION FOR INHOMOGENEOUS PLASMA DIAGNOSTIC

2021 ◽  
pp. 163-170
Author(s):  
Y.V. Siusko ◽  
Yu.V. Kovtun
Keyword(s):  
Inhomogeneous Plasma ◽  
Average Density ◽  
Electron Collision ◽  
Plasma Diagnostic ◽  
Plasma Parameters ◽  
Peripheral Plasma ◽  
Electron Collision Frequency ◽  
Microwave Diagnostics ◽  
The Magnetic Field

A brief review of the main microwave diagnostics methods of inhomogeneous plasma based on the refraction of microwaves is given. These methods make it possible to determine the plasma density distribution, the magnetic field distribution, the electron collision frequency, and the electron temperature profile. In addition, the determination of the average density of the peripheral plasma layers and the local inhomogeneities of the rotating plasma are also possible. The effect of refraction on the accuracy of determining the plasma parameters by using microwave methods for plasma diagnostics is considered.

Thomson scattering from Langmuir fluctuations in a parabolic layer of a collisional plasma

2018 ◽  
Vol 96 (9) ◽  
pp. 1053-1058 ◽  
Author(s):  
V.A. Puchkov
Keyword(s):  
Plasma Layer ◽  
Collision Frequency ◽  
Thomson Scattering ◽  
Distribution Functions ◽  
Electron Collision ◽  
Plasma Parameters ◽  
Probe Wave ◽  
Electron Collision Frequency ◽  
Collisional Damping ◽  
Plasma Line

Thomson scattering of a probe wave by the Langmuir fluctuations inside a plasma layer with a parabolic density profile is considered. The collisional damping of plasma fluctuations is taken into account. The plasma line part of the scattered spectrum is calculated depending on the layer thickness, electron collision frequency, and the form of the distribution functions for the electrons and ions. Simple analytic expressions for the plasma line shape and characteristic spectrum width are found. It is shown that this plasma line is asymmetric, and the asymmetry depends on the layer type (maximum or minimum). Some important plasma parameters, such as the electron collision frequency and the sign of the electron density deviation inside the layer can be obtained from the plasma line spectrum calculated in this paper.

Gleichzeitige Bestimmung von Parametern der Ionosphären-D-Region beim Vorliegen eines negativen Höhengradienten der Elektronenkonzentration

1981 ◽  
Vol 36 (5) ◽  
pp. 510-515
Author(s):  
W. Muschler
Keyword(s):  
Concentration Profile ◽  
Electron Concentration ◽  
Coupling Parameter ◽  
Electron Collision ◽  
Model Calculations ◽  
Electron Collision Frequency ◽  
Complex Wave ◽  
D Region ◽  
Propagation Experiment

Abstract Preceding papers were concerned with the principles of a wave propagation experiment, which appeared suitable for a simultaneous determination of electron concentration Ne and electron collision frequency v in a magnetoplasma. The complex wave polarization was used being defined by field strength ratios. In former model calculations the electron concentration profile was characterized by exclusively positive height gradients. In this paper considerations are extended to an electron concentration profile with gradient inversion. Calculations on error propagation and wave damping and an estimation of the coupling parameter do not lead to new or serious restrictions in the question of the applicability of the method.

Über ein Verfahren zur gleichzeitigen Bestimmung von Elektronenkonzentration und Elektronenstoßzahl in einem homogenen isotropen oder in einem langsam veränderlichen Plasma

1970 ◽  
Vol 25 (1) ◽  
pp. 106-114
Author(s):  
W. Muschler
Keyword(s):  
Refractive Index ◽  
Electron Concentration ◽  
Collision Frequency ◽  
Complex Refractive Index ◽  
Electron Collision ◽  
Height Range ◽  
Reflected Waves ◽  
Electron Collision Frequency ◽  
D Region

Abstract A method is described, which allows determination of the complex refractive index of a plasma by separate measurement of the E-and H-component of an electromagnetic wave. By means of the complex refractive index simultaneously electron concentration and electron collision frequency of the medium can be stated.The measuring frequency depends upon absorption, precision requirements, and - for a locally varying medium - upon the availability range of theory used.General considerations are applied to a plasma model (terrestrial ionosphere without magnetic field): Simultaneous measurement of electron concentration and electron collision frequency should be well possible within a height range corresponding to the terrestrial D-region. In higher regions determination of the (decreasing) electron collision frequency becomes more and more difficult, whereas possibilities for determination of the (increasing) electron concentration seem to improve.The influence of reflected waves is considered in a following paper 4.

Gleichzeitige Bestimmung von Elektronenkonzentration und Elektronenstoßzahl in einem örtlich langsam veränderlichen Magnetoplasma (Teil II) / Simultaneous Determination of Electron Concentration and Electron Collision Frequency in a Locally Slowly Varying Magnetoplasma (II)

1974 ◽  
Vol 29 (1) ◽  
pp. 75-83
Author(s):  
W. Muschler
Keyword(s):  
Simultaneous Determination ◽  
Electron Concentration ◽  
Collision Frequency ◽  
Preceding Paper ◽  
Numerical Calculations ◽  
Electron Collision ◽  
Plasma Model ◽  
Electron Collision Frequency ◽  
Coupled Wave Equations

A preceding paper was concerned with the principles of a wave propagation experiment. These appeared suitable for a simultaneous determination of electron concentration Ne and of electron collision frequency v in a magnetoplasma. They considered measurements of the refractive index n and of wave polarization ϱ, both of which being determined by field strength ratios. In this paper supplementary numerical calculations are carried out using a plasma model that corresponds to conditions observable in the earth’s lower day time ionosphere and that is characterized by exclusively positive gradients of Ne . Furthermore, a modification of the original principle is discussed renouncing measurements of n and using only those of ϱ. Numerical calculations on error propagation demonstrate a significant superiority of the modified version. WKB solutions of coupled wave equations are used. As the plasma model includes local variations of the plasma parameters, the theory can be applied only to limited height and frequency intervals. These are deduced from the coupling parameter Ψ.

scholarly journals Bestimmung des komplexen Brechungsindex eines Plasmas mittels des Ausbreitungsverfahrens beim Auftreten reflektierter Wellen

1970 ◽  
Vol 25 (4) ◽  
pp. 482-487
Author(s):  
W. Muschler
Keyword(s):  
Refractive Index ◽  
Wave Propagation ◽  
Simultaneous Determination ◽  
Electron Concentration ◽  
Collision Frequency ◽  
Complex Refractive Index ◽  
Preceding Paper ◽  
Electron Collision ◽  
Electron Collision Frequency

Abstract In a preceding paper a propagation method has been described that allows simultaneous determination of electron concentration and electron collision frequency in a slowly varying plasma - using its complex refractive index. A regular progressive damped wave had been assumed. In this paper the treatment is extended to the case that the original wave is superimposed by a reflected one. The calculations show that for distinct points in the direction of wave propagation the determination of both modulus and argument of the complex refractive index is again possible. The discrete sequence of measuring points does not restrict the local resolution of the method.

scholarly journals What Density of Magnetosheath Sodium Ions Can Provide the Observed Decrease in the Magnetic Field of the “Double Magnetopause” during the First MESSENGER Flyby?

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1168
Author(s):  
Elena Belenkaya ◽  
Ivan Pensionerov
Keyword(s):  
Magnetic Field ◽  
Analytical Approach ◽  
Field Structure ◽  
Sodium Ions ◽  
Plasma Parameters ◽  
Calculation Results ◽  
Magnetizing Current ◽  
The Magnetic Field ◽  
Density Excess

On 14 January 2008, the MESSENGER spacecraft, during its first flyby around Mercury, recorded the magnetic field structure, which was later called the “double magnetopause”. The role of sodium ions penetrating into the Hermean magnetosphere from the magnetosheath in generation of this structure has been discussed since then. The violation of the symmetry of the plasma parameters at the magnetopause is the cause of the magnetizing current generation. Here, we consider whether the change in the density of sodium ions on both sides of the Hermean magnetopause could be the cause of a wide diamagnetic current in the magnetosphere at its dawn-side boundary observed during the first MESSENGER flyby. In the present paper, we propose an analytical approach that made it possible to determine the magnetosheath Na+ density excess providing the best agreement between the calculation results and the observed magnetic field in the double magnetopause.

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