Interferometric Measurements of Time‐Dependent Electron Density in the Xenon ``Pinched'' Plasma Laser

1971 ◽  
Vol 42 (5) ◽  
pp. 1914-1916 ◽  
Author(s):  
A. Papayoanou ◽  
I. Gumeiner
Keyword(s):  
Electron Density ◽  
Time Dependent ◽  
Plasma Laser ◽  
Pinched Plasma

The propagation of a transverse electromagnetic wave in a nonlinear, anisotropic, time-dependent plasma medium

1968 ◽  
Vol 46 (7) ◽  
pp. 889-905
Author(s):  
Robert J. Papa
Keyword(s):  
Energy Balance ◽  
Plane Wave ◽  
Electron Temperature ◽  
Electron Density ◽  
Balance Equation ◽  
Energy Balance Equation ◽  
Time Dependent ◽  
Time Varying ◽  
Circularly Polarized ◽  
Elliptically Polarized

In a previous paper, a one-dimensional, inhomogeneous model was considered in describing the nonlinear interaction of a radiofrequency plane wave with a time-varying plasma. This paper extends the analysis to the anisotropic case, in which an elliptically polarized plane wave incident upon an electron-density profile induces changes in the electron density and electron temperature. A d-c. magnetic field parallel to the electron-density gradients causes the elliptically polarized wave to split into two distinct modes, a right-hand circularly polarized and a left-hand circularly polarized mode. The two modes are coupled through an energy-balance equation that governs the behavior of the electron temperature. The time-dependent response of the plasma may be found by numerically integrating an energy-balance equation and a continuity equation. The solution to the wave equation for the time-varying, inhomogeneous, anisotropic medium may be obtained through the use of the WKB approximation. The time scales for electron-temperature and electron-density changes are found to vary with incident flux, incident-wave ellipticity, and appropriate normalized plasma parameters.

Vibrational nitrogen concentration in the ionosphere and its dependence on season and solar cycle

1995 ◽  
Vol 13 (11) ◽  
pp. 1164-1171 ◽  
Author(s):  
A. E. Ennis ◽  
G. J. Bailey ◽  
R. J. Moffett
Keyword(s):  
Mathematical Model ◽  
Solar Cycle ◽  
Electron Density ◽  
Geomagnetic Field ◽  
Nitrogen Concentration ◽  
Time Dependent ◽  
Electron Content ◽  
Vibrationally Excited ◽  
F Region ◽  
Excited Nitrogen

Abstract. A fully time-dependent mathematical model, SUPIM, of the Earth's plasmasphere is used in this investigation. The model solves coupled time-dependent equations of continuity, momentum and energy balance for the O+, H+, He+, N+2, O+2, NO+ ions and electrons; in the present study, the geomagnetic field is represented by an axial-centred dipole. Calculation of vibrationally excited nitrogen molecules, which has been incorporated into the model, is presented here. The enhanced model is then used to investigate the behaviour of vibrationally excited nitrogen molecules with F10.7 and solar EUV flux, during summer, winter and equinox conditions. The presence of vibrational nitrogen causes a reduction in the electron content. The diurnal peak in electron content increases linearly up to a certain value of F10.7, and above this value increases at a lesser rate, in agreement with previous observations and modelling work. The value of F10.7 at which this change in gradient occurs is reduced by the presence of vibrational nitrogen. Vibrational nitrogen is most effective at F-region altitudes during summer daytime conditions when a reduction in the electron density is seen. A lesser effect is seen at equinox, and in winter the effect is negligible. The summer reduction in electron density due to vibrational nitrogen therefore reinforces the seasonal anomaly.

Many-Electron Problem in Terms of the Density: From Thomas–Fermi to Modern Density-Functional Theory

2003 ◽  
Vol 02 (02) ◽  
pp. 301-322 ◽  
Author(s):  
Manoj K. Harbola ◽  
Arup Banerjee
Keyword(s):  
Density Functional Theory ◽  
Perturbation Theory ◽  
Electron Density ◽  
Current Density ◽  
Density Functional ◽  
Electron System ◽  
Time Dependent ◽  
Functional Theory ◽  
Thomas Fermi ◽  
Alkali Metal Clusters

In this paper we focus on the use of electron density and current-density as basic variables in describing a many-electron system. We start with a discussion of the seminal Thomas–Fermi theory and its extension by Bloch for time-dependent hamiltonians. We then present modern density-functional theory (for both time-independent and time-dependent hamiltonians) and approximations involved in implementing it. Also discussed is perturbation theory in terms of electron density and its use for calculating various response properties and related quantities. In particular, van der Waals coefficient C6 is calculated using density and current density in time-dependent perturbation theory. Throughout the paper, results for alkali-metal clusters are presented to demonstrate the strength of density-based theories.

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