Electron density profiles in the lower ionosphere deduced from long path VLF wave propagation

Rinnert, K.

doi:10.1029/rs008i010p00829

Cited by 3 publications

(2 citation statements)

References 17 publications

(6 reference statements)

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“…The electron density profiles in the D and E region can be measured by various techniques such as a low frequency sounder (WATTS, 1958;SHELLMAN, 1970;WAKAI, 1971), the cross-modulation method (HOLT et al, 1962), partial reflection method (BELROSE and BURKE, 1964;HAUG, 1966;BELROSE et al, 1972), riometer observation (PARTHASARATHY et al, 1963;LERFALD et al, 1964), radio wave absorption measurements (ELLING, 1974), incoherent scatter radar (BANKS et al, 1974), phase measurement of VLF propagation (RINNERT, 1973), and VHF propagation (WATKINS and ESSEX, 1973). Also, the direct measurement of the ionosphere by using sounding rocket is a powerful method (JESPERSEN et al, 1964(JESPERSEN et al, , 1966MECHTLY and SMITH, 1970;SECHRIST, 1970;DERBLOM and LADELL, 1973).…”

Section: Introductionmentioning

confidence: 99%

Relation between lower ionospheric electron density profiles and cosmic noise absorption during auroral zone disturbances.

Miyazaki¹

1975

J. geomagn. geoelec

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Eight rockets among a total of twenty-one rocket experiments by the 12th, 13th and 14th Japanese Antarctic Research Expedition parties were launched during auroral disturbances at night at Syowa Station, Antarctica between 1971 and 1973. The electron density profiles in the lower ionosphere between about 50 km and 130 km under various disturbed conditions were obtained by rocketborne radio frequency probes and electrostatic probes.The collision frequency profile is derived from the electron density profiles and cosmic noise absorption measurements.There exists a maximum absorption layer in the region between 75 km and 85 km, and this location of the layer is not strongly dependent on the magnitude of the ionospheric dis-turbance. An increase in the electron density, especially in the D and E region between about 75 km and 110 km has a good correlation with cosmic noise absorption; the following empirical formulae are obtained from the observational results: , hm-2x+100, where 4n6(cm-3) is the maximum increment of the electron density from the quiet level, hm(km) is the height of the maximum increment of the electron density and x (dB) is the cosmic noise absorption.

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Section: Introductionmentioning

confidence: 99%

Relation between lower ionospheric electron density profiles and cosmic noise absorption during auroral zone disturbances.

Miyazaki¹

1975

J. geomagn. geoelec

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“…This was essential as the ionospheric parameters are solar zenith angle dependent for long propagation paths. To reproduce the spatial signal variation using LWPC, Wait's exponential profiles [ Wait‐and‐Spies , ; Cummer et al , ; Clilverd et al , ; Pal et al , ], related to the sharpness parameter β and VLF reflection height parameter

h^{'}

, which control the electron density profile of D layer [ Rinnert , ], have been used. The simulations were done only for two specific solar flux variation states: (i) when the entire path is illuminated ( β = 0.5 km −1 and

h^{'} = 74.0

km) and (ii) when the entire path is dark ( β = 0.59 km −1 and

h^{'} = 85.0

km).…”

Section: Introductionmentioning

confidence: 99%

Modeling of long‐path propagation characteristics of VLF radio waves as observed from Indian Antarctic station Maitri

2015

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Propagation of very low frequency (VLF) radio signal through the Earth‐ionosphere waveguide depends strongly on the plasma properties of the ionospheric D layer. Solar extreme ultraviolet radiation plays the central role in controlling physical and chemical properties of the lower ionospheric layers and hence determining the propagation characteristics of a VLF signal. The nature of interference among different propagating modes varies widely with the length of the propagation path. For a very long path, exposure of solar radiation and thus the degree of ionization vary by a large amount along the path. This influences the VLF signal profile by modulating the sky wave propagation. To understand the propagation characteristics over such a long path, we need a thorough investigation of the chemical reactions of the lower ionosphere which is lacking in the literature. Study of radio signal characteristics in the Antarctic region during summer period in the Southern Hemisphere gives us a unique opportunity to explore such a possibility. In addition, there is an extra feature in this path—the presence of solar radiation and hence the D region for the whole day during summer in at least some sections of the path. In this paper, we present long‐distance propagation characteristics of VLF signals transmitted from VTX (18.2 kHz) and NWC (19.8 kHz) transmitters recorded at the Indian permanent station Maitri (latitude 70° 45′S, longitude 114° 40′E) in 2007–2008. A very stable diurnal variation of the signal has been obtained with no signature of nighttime fluctuation due the presence of 24 h of sunlight. Using ion production and recombination profiles by solar irradiance and incorporating D region ion chemistry processes, we calculate the electron density profile at different heights. Using this profile in the Long Wavelength Propagation Capability code, we are able to reproduce the amplitude of VLF signal.

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VLF modal interference over west-east paths

Lynn¹

1977

Journal of Atmospheric and Terrestrial Physics

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Electron density profiles in the lower ionosphere deduced from long path VLF wave propagation

Cited by 3 publications

References 17 publications

Relation between lower ionospheric electron density profiles and cosmic noise absorption during auroral zone disturbances.

Relation between lower ionospheric electron density profiles and cosmic noise absorption during auroral zone disturbances.

Modeling of long‐path propagation characteristics of VLF radio waves as observed from Indian Antarctic station Maitri

VLF modal interference over west-east paths

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