Modelling the Electron Density Distribution in the July 1991 Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 535-539 ◽  
Author(s):  
F. Clette ◽  
P. Cugnon ◽  
J.-R. Gabryl
Keyword(s):  
Magnetic Field ◽  
Density Distribution ◽  
Electron Density ◽  
Legendre Polynomials ◽  
Electron Density Distribution ◽  
Large Scale ◽  
Symmetry Axis ◽  
Rotation Axis ◽  
Magnetic Field Axis ◽  
The Mean

AbstractUsing intensity and polarization maps computed from white-light observations of the July 11, 1991 solar eclipse, we present axisymmetrical models of the large-scale electron density distribution in the corona. These models are based on an expansion in Legendre polynomials, and are flexible enough to fit individual features, like streamers and holes. Furthermore, as the symmetry axis of our models can take any orientation, we consider two plausible configurations, aligned on the rotation axis or the mean bipolar magnetic field axis. Their respective abilities to reproduce a strongly non-spherical global magnetic structure are then compared.

The electron density distribution in the topside ionosphere I. Magnetic-field-alined strata

1964 ◽  
Vol 281 (1387) ◽  
pp. 450-458 ◽  
Keyword(s):  
Magnetic Field ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Probe ◽  
Electron Density Distribution ◽  
Topside Ionosphere ◽  
Electric Permittivity ◽  
Measuring Head ◽  
Flat Disk ◽  
Method Of Measurement

1. The method of measurement of electron density The measurement of the electron density distribution in the topside ionosphere is made by a radio-frequency electron probe which was developed for this satellite. This probe measures the local electric permittivity of the medium in the vicinity of the satellite using a probing frequency of 10 Mc/s and from a knowledge of the permittivity the electron density is readily calculated. The electrodes consist of a pair of flat disk-shaped grids, 4 in. in diameter and spaced 3 1|2 in. apart. These grids are supported on the ends of two short tubes which, in turn, are mounted on a small junction box. This complete unit, which forms the measuring head, is fixed on the end of a retractable boom which extends about 3 ft. from the hull of the satellite. The permittivity is measured in terms of the current that flows between the two electrodes in response to a constant applied signal of 3 V r.m.s. This signal is provided by a 10 Mc/s crystal controlled oscillator, the amplitude being electronically stabilized at the above value.

scholarly journals The Radio Luminosity of Pulsars and the Distribution of Interstellar Electron Density

2001 ◽  
Vol 182 ◽  
pp. 175-179
Author(s):  
R.R. Andreasyan ◽  
T.G. Arshakian
Keyword(s):  
Density Distribution ◽  
Electron Density ◽  
Time Variation ◽  
Electron Density Distribution ◽  
Large Scale ◽  
Radio Luminosity ◽  
The Galaxy ◽  
Dispersion Measures ◽  
Average Electron ◽  
Spiral Arm

AbstractThe radio luminosities of pulsars are given as functions of their period and the time variation of the period. The parameters of that dependence are calculated and independent distances are determined for pulsars. The average electron densities toward the pulsars are determined from the known dispersion measures. The results obtained are used to study the large-scale electron density distribution in the Galaxy. The distribution maximum lies in the vicinity of the Sagittarius spiral arm. The electron density falls off exponentially in the regions between spiral arms.

scholarly journals The He-strong star HD 96446: oblique rotator or pulsating magnetic variable?

1994 ◽  
Vol 162 ◽  
pp. 169-170
Author(s):  
G. Mathys
Keyword(s):  
Magnetic Field ◽  
Line Intensity ◽  
Large Scale ◽  
Longitudinal Magnetic Field ◽  
Rotation Axis ◽  
Weighted Average ◽  
Line Of Sight ◽  
Order Moment ◽  
Stellar Rotation ◽  
The Mean

HD 96446 is a B2p He-strong star, in which a large-scale organized magnetic field is present. From spectra recorded in both circular polarizations, various moments of this magnetic field have been repeatedly determined, among which the mean longitudinal magnetic field and the crossover. The mean longitudinal magnetic field 〈Hz〉 is the line-intensity weighted average over the visible stellar hemisphere of the line-of-sight component of the magnetic vector. The crossover, ve sin i 〈x Hz〉,is the product of the projected equatorial velocity, ve sini, and of the mean asymmetry of the longitudinal magnetic field, 〈x Hz〉. The latter is the line-intensity weighted first-order moment about the plane defined by the line of sight and the stellar rotation axis of the component of the magnetic field along the line of sight.

Electron-density distribution in CuFeS2 as determined by 63,65Cu NMR in an internal magnetic field

2013 ◽  
Vol 80 (3) ◽  
pp. 351-356 ◽  
Author(s):  
A. I. Pogoreltsev ◽  
A. N. Gavrilenko ◽  
V. L. Matukhin ◽  
B. V. Korzun ◽  
E. V. Schmidt
Keyword(s):  
Magnetic Field ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Internal Magnetic Field

scholarly journals Hectometer and Kilometer Solar Observations

1980 ◽  
Vol 86 ◽  
pp. 405-413
Author(s):  
R. G. Stone
Keyword(s):  
Density Distribution ◽  
Radio Source ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Large Scale ◽  
Three Dimensional ◽  
Dipole Antennas ◽  
Magnetic Field Topology ◽  
Solar Observations ◽  
Field Geometry

Three dimensional “snapshots” of the large scale solar magnetic field topology as well as the solar wind electron density distribution from about 0.1 to 1 AU are obtained by tracking traveling solar radio bursts at hectometer and kilometer wavelengths with instruments aborad the ISEE-3 satellite and the HELIOS-2 solar probe. Both instruments observe in the frequency range from 30 kHz to 1 MHz and both are equipped with dipole antennas located in the vehicle spin plane. ISEE-3 also has a dipole along the spin axis and the signals from the two ISEE-3 antennas are combined to give the azimuth and elevation angles of the radio source. Triangulation between HELIOS-2 and ISEE-3 provides the additional observation necessary to uniquely determine the position of the radio source in space at each observing frequency. The techniques will be outlined, and illustrated by an example of the three dimensional field geometry and electron density distribution determined by the observations.

scholarly journals Model modulation to add smaller scale structures to large scale electron density models

2005 ◽  
Vol 3 ◽  
pp. 441-447
Author(s):  
R. Leitinger ◽  
E. Feichter ◽  
M. Rieger
Keyword(s):  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Large Scale ◽  
Scale Model ◽  
Spatial Structures ◽  
Large Scale Model ◽  
Modulation Model ◽  
Anchor Points ◽  
Scale Structures

Abstract. Usually regional and global electron density models provide large scale spatial structures only and smooth out the smaller scale features of the electron density distribution. We present a method to modulate existing electron density models by multiplication: M(h, φ, λ, t) = L(h, φ, λ, t) × S1(h, φ, λ, t) × S2(h, φ, λ, t) × ... Sn(h, φ, λ, t) M: resulting electron density distribution, L: large scale model, S1...Sn: modulating models for n the smaller scale structures; h: height; φ, λ: geographic coordinates, t: Universal Time. There are no restrictions to the nature of the large scale model provided it takes height and horizontal coordinates as input. Examples are models of the "profiler" type which use large scale "maps" for profile anchor points (e.g., E, F1, F2 peak properties) like the International Reference Ionosphere (IRI). Typical examples for smaller scale structures are ridges, troughs and wavelike disturbances. The advantage of modulation by multiplication is that there is no danger to get zero or negative values of electron density as long as the background and modulations are >0 everywhere. For each modulation model, unity means "undisturbed".

scholarly journals Equilibrium of a Pinch Discharge with a Transverse Rotating Magnetic Field

1965 ◽  
Vol 18 (4) ◽  
pp. 309 ◽  
Author(s):  
HA Blevin ◽  
RB Miller
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Rotating Magnetic Field ◽  
Numerical Examples ◽  
Ionized Plasmas ◽  
Partially Ionized Plasmas ◽  
Partially Ionized

The electron density distribution in a linear pinch discharge with a transverse rotating magnetic field is calculated for partially ionized plasmas. Numerical examples are given for distributions in the plasma with and without externally applied axial magnetic fields, and with different degrees of ionization.

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