Correlation method of determining the electron concentration in the D-region of the ionosphere

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.

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D-region electron concentration profile produced by the July 9, 1962, nuclear detonation

Journal of Geophysical Research Atmospheres ◽

10.1029/ja074i024p05737 ◽

1969 ◽

Vol 74 (24) ◽

pp. 5737-5742 ◽

Cited By ~ 1

Author(s):

A. T. Jusick ◽

D. R. Furman

Keyword(s):

Concentration Profile ◽

Electron Concentration ◽

D Region

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

Zeitschrift für Naturforschung A ◽

10.1515/zna-1970-0118 ◽

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.

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Application of cross correlation to HREM images of surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128080 ◽

1987 ◽

Vol 45 ◽

pp. 754-755

Author(s):

D. E. Luzzi ◽

L. D. Marks ◽

M. I. Buckett

Keyword(s):

Cross Correlation ◽

A Priori ◽

Matrix Material ◽

Correlation Method ◽

Accurate Knowledge ◽

Complex Image ◽

Fourier Filtering ◽

The Matrix ◽

Low Pass ◽

Data Reduction Technique

As the HREM becomes increasingly used for the study of dynamic localized phenomena, the development of techniques to recover the desired information from a real image is important. Often, the important features are not strongly scattering in comparison to the matrix material in addition to being masked by statistical and amorphous noise. The desired information will usually involve the accurate knowledge of the position and intensity of the contrast. In order to decipher the desired information from a complex image, cross-correlation (xcf) techniques can be utilized. Unlike other image processing methods which rely on data massaging (e.g. high/low pass filtering or Fourier filtering), the cross-correlation method is a rigorous data reduction technique with no a priori assumptions.We have examined basic cross-correlation procedures using images of discrete gaussian peaks and have developed an iterative procedure to greatly enhance the capabilities of these techniques when the contrast from the peaks overlap.

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