Nose whistler dispersion as a measure of magnetosphere electron temperature

Guthart, H.

doi:10.6028/jres.069d.152

Cited by 7 publications

(8 citation statements)

References 6 publications

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“…It is important to note that the zero level is not shifted in lossy signal, only the amplitude is decreased. An increase in colli- (Guthart, 1965)). Observed and simulated are marked by arrow.…”

Section: Theoretical Formulation and Computational Resultsmentioning

confidence: 99%

Simulation of whistler mode propagation for low latitude stations

Singh

Ferencz

2014

Earth Planet Sp

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Representing lightning discharge current source by a Dirac delta function, Maxwell's equations are solved to derive the expression for wave-electric field as a function of frequency and distance including the effect of interparticle collisions. The exact time-dependence of the propagating non-monochromatic signal for the realistic magnetospheric model is computed for low latitude stations (in India). The computation is extended for the wave propagating through different regions of the magnetosphere and results are compared with the measured data. Points of agreements and differences are illuminated.

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Section: Theoretical Formulation and Computational Resultsmentioning

confidence: 99%

Simulation of whistler mode propagation for low latitude stations

Singh

Ferencz

2014

Earth Planet Sp

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“…The thermal motion of the particles tends to lower the effective gyrofrequency of a significant number of the particles and thus to slightly depress the nose frequency of the whistler. However, the thermal effects also tend to increase the travel time of the whistler [Guthart, 1965;Scar/, 1962]. The result is that a datum point on the equatorial profile is plotted slightly too high in equatorial radius but too low in density.…”

Section: Discussion O• the Estimate O• 1 El/cm • At 7 R• A Number Omentioning

confidence: 99%

Whistler studies of the plasmapause in the magnetosphere: 2. Electron density and total tube electron content near the knee in magnetospheric ionization

Angerami¹,

Carpenter²

1966

J. Geophys. Res.

249

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A study has been made of electron density and total electron content in tubes of force near the knee in magnetospheric ionization. It was based on whistler observations made at Eights, Antarctica, in July and August 1963, under conditions of steady, moderate geomagnetic agitation (Kp = 2-4). During the period 0100-0400 LT, the electron density near the equatorial plane at a geocentric distance of 4 Rr drops a factor of 30-100 within a distance of less than 0.15 Rr. The corresponding change in tube content above 1 cm 2 at 1000 km is • factor of about 10 within less than a degree of latitude. The afternoon profiles are gen-erMly similar to the postmidnight results. In the afternoon the profiles are often well defined outside the knee, falling smoothly to about 1 el/cm 8 at 7 RE. Both the equatorial and tube content profiles show a definite repeatability between observations at a given local time and under conditions of moderate, steady geomagnetic agitation. DiurnM effects are evident, with amplitude differing from point to point on the profiles. The problem of the field-line distribution of ionization has been studied with a view to minimizing error in the profiles. Experimental and theoretical support has been found for using a diffusive-equilibrium distribution along the field lines inside the knee and a 'collisionless' model, behaving approximately as N• o: R -4, along the field lines outside the knee. A study of error shows that the uncertainty in individual points on the knee profiles is evewwhere less than a factor of ñ2, and on the content profiles less than • factor of ñ1.5. •On leave from Escola Polit•cnica, Universidade de S•o Paulo, Brasil.Reference profile. As a reference for the results on the knee, we have calculated equatorialdensity and total-tube-content profiles corresponding to the whistler shown on the upper record in Figure 1. This event was recorded at about 0150 LT during extremely quiet planetary magnetic conditions, when the equatorial distance to the knee is expected to be large (see K-l). Thus the many components in the whistler represent a broad range of field-line paths inside the knee. Figure 2 shows the calculated equatorial profile of electron density; Figure 3, the corresponding profile of total electron content in a tube of force versus dipole latitude at 1000 km. The latter profile is calculated for a tube with cross section of 1 cm -ø at 1000 km altitude and extending from 1000 km to the equatorial plane.In Figures 2 and 3, and in many of the following figures, there are three types of data symbol, corresponding to three levels of precision in the measurements. The solid symbols represent highest precision; isolated open sym- 711

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“…A different approach was taken by Guthart [40] who attempted to estimate magnetospheric electron temperature from its effect on whistler group velocity, assuming a gyrofrequency model electron distribution. He cted that the thermal effect on whistler spectra should be largest at frequencies near the upper cut-off frequency of nose whistlers.…”

Section: Res E Ults and Discussionmentioning

confidence: 99%

Estimation of Magnetospheric Plasma Parameters from Whistlers Observed at Low Latitudes

Altaf¹,

Ahmad²,

Banday³

2013

IJAA

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Whistler observations during nighttimes made at low latitude Indian ground stations Jammu (geomag. lat., 29˚26'N; L = 1.17), Nainital (geomag. lat., 19˚1'N; L = 1.16) and Varanasi (geomag. lat., 14˚55'N; L = 1.11) are used to deduce electron temperatures and electric field in the vicinity of the magnetospheric equator. The accurate curve fitting and parameter estimation technique are used to compute nose frequency and equatorial electron densities from the dispersion measurements of short whistlers recorded at Jammu, Nainital and Varanasi. In this paper, our aim is to estimate the Magnetospheric electron temperatures and electric field from the dispersion analysis of short whistlers observed at low latitudes by using different methods. The results obtained are in good agreement with the results reported by other workers.

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Nose whistler dispersion as a measure of magnetosphere electron temperature

Cited by 7 publications

References 6 publications

Simulation of whistler mode propagation for low latitude stations

Simulation of whistler mode propagation for low latitude stations

Whistler studies of the plasmapause in the magnetosphere: 2. Electron density and total tube electron content near the knee in magnetospheric ionization

Estimation of Magnetospheric Plasma Parameters from Whistlers Observed at Low Latitudes

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