Observations on the Propagation Constant of the EarthIonosphere Waveguide in the Frequency Band 8 c/s to 16 kc/s

Chapman, F. W.; Jones, D. Llanwyn; Todd, Janet; Challinor, R.A.

doi:10.1002/rds19661111273

Cited by 60 publications

(31 citation statements)

References 31 publications

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“…Table 1 shows the hiss intensities in power flux density at Moshiri and Kagoshima and the attenuation values between the two stations for the first and second peaks. It is found from Table 1 that the attenuation values are larger at 5 kHz than at 8 kHz, which result is apparently consistent with the attenuation rates presented by CHAPMANN et al (1966); 5 dB/Mm and 4 dB/Mm in the nighttime, and 10 dB/Mm and 8 dB/ Mm in the daytime at 5 kHz and 8 kHz, respectively. The distance between Moshiri and Kagoshima is Intensity unit: 10-n W/m2(Hz).…”

Section: Observations Of Vlf Emissions and The Analysis Of Frequency supporting

confidence: 87%

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Low-Latitude VLF Hiss Associated with the Severe Magnetic Storm on October 19-21, 1989.

Nishino¹,

Tanaka²

1994

J. geomagn. geoelec

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Low-latitude VLF hiss was observed at dawn time at Moshiri (L = 1.6) and Kagoshima (L = 1.2), Japan during 20hOOm UT to 23h30m UT on October 20, associated with the severe magnetic storm (Kp = 8) during October 19-21,1989. The VLF hiss with a band-limited spectrum exhibited an increase of frequency (fmax) of the maximum energy with local time. Based on the quasi-linear model for hisstype mid-latitude VLF emissions developed by SAZHIN (1984) and using electron density data by EXOS-D satellite, it is estimated that injected electrons of about 5 keV associated with the maximum depression of the magnetic H-component around 13h30m UT on October 20 contribute to the generation of the VLF hiss at dawn time around L = 4.8 of the magnetospheric equatorial region. The plasmapause has been disrupted due to the strong magnetospheric disturbances when the VLF hiss was observed. The increase of fmax may be due to a combined effect of the energy dependences of different drift starting longitudes of the hot electrons injected in the evening sector and of the drift velocities of the electrons encircling the Earth, and a temporal variation of the cold electron density in the generation region at dawn sector. Furthermore it is implied that the VLF hiss has penetrated through the ionosphere at the higher latitude than that of Moshiri and then propagated toward the low-latitude stations in the Earth-ionosphere waveguide mode.

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Section: Observations Of Vlf Emissions and The Analysis Of Frequency supporting

confidence: 87%

“…4) Propagation loss from the emitting point to the ground station. The loss is estimated to be 16 dB in the Earth-ionosphere wave-guide mode for the propagation distance of about 2000 km (CHAPMANN et al, 1966), as described below.…”

Section: Observations Of Vlf Emissions and The Analysis Of Frequency mentioning

confidence: 99%

Low-Latitude VLF Hiss Associated with the Severe Magnetic Storm on October 19-21, 1989.

Nishino¹,

Tanaka²

1994

J. geomagn. geoelec

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“…The difference between these is: From this, the group velocity can be calculated as: Once V is known, the traveling time of the direct wave from the source to the recording station (SOD/V) can be calculated. The calculated group velocities are around 0.8c (c is the speed of light in vacuum) a value characteristic for ELF waves [ Chapman et al , 1966]. If this traveling time is extracted from the detection time of the event, the beginning time of the source activity can be determined.…”

Section: Resultsmentioning

confidence: 99%

Gigantic jets produced by an isolated tropical thunderstorm near Réunion Island

et al. 2011

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[1] Five gigantic jets (GJs) have been recorded with video and photograph cameras on 7 March 2010 above an isolated tropical storm east of Réunion Island. Three of them were produced before the storm reached its coldest cloud top temperature (approximately −81°C), and two others occurred during the cloud extension. Thanks to the close distance of observation (∼50 km), the luminosity within the cloud was recorded, and the events are analyzed in unprecedented detail. The tops of the GJs are estimated between 80 and 90 km. All these GJs are accompanied by long, continuous cloud illumination, and they are preceded and followed by intermittent optical flashes from the cloud, most of time without any cloud-to-ground (CG) flash simultaneously detected, which suggests they originated mainly as intracloud discharges and without any charge transfer to Earth. The CG lightning activity is observed to cease a few tens of seconds before the jets. According to ELF data recorded at Nagycenk, Hungary, the five GJs serve to raise negative charge. Their duration ranges from 333 to 850 ms. The leading jet has the most variable duration (33-167 ms) and propagates faster at higher altitudes. The trailing jet exhibits a continuous decrease of luminosity in different parts of the jet (lower channel, transition zone and, for most events, carrot sprite-like top) and in the cloud, with possible rebrightening. The lower channels (∼20-40 km altitude) produce blue luminosity which decreases with altitude and become more and more diffuse with time. The transition zone (around 40-65 km) consists of bright red, luminous beads slowly going up (∼10 4 m s −1), retracing the initial leading jet channels.Citation: Soula, S., O. van der Velde, J. Montanya, P. Huet, C. Barthe, and J. Bór (2011), Gigantic jets produced by an isolated tropical thunderstorm near Réunion Island,

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“…Within the Earth-ionosphere waveguide this pulse, or sferic, is not significantly dispersed and can travel considerable distances. Waveguide attenuation at 2kHz is in the range 15-30dB/Mm (Wait, 1962;Chapman et al, 1966;Bernstein et al, 1974), where the upper limit applies during the day and the lower limit obtains at night. However, there also is a zonal propagation asymmetry: eastward propagation appears to suffer less attrition than westward (Crombie, 1963).…”

Section: Introductionmentioning

confidence: 99%

Global lightning distribution and whistlers observed at Dunedin, New Zealand

et al. 2010

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Abstract. Whistlers observed at Dunedin, New Zealand, are an enigma since they do not conform to the classical model of whistler production developed by Storey (1953). It is generally accepted that the causative lightning stroke for a whistler observed on the ground at a particular location was located in the neighbourhood of the conjugate point, and generated an electromagnetic signal which propagated in a plasmaspheric duct stretched along a magnetic field line linking the two hemispheres. The causative stroke is thought to have occurred within reasonable proximity of one footpoint of this field line, while the observer was located in the vicinity of the other footpoint. Support for this model has come from a number of previous studies of whistler-lightning observations and whistler-induced particle precipitation. However, as demonstrated here, this model does not always apply.Whistlers detected at Dunedin are nearly as common as those at Tihany, Hungary, despite there being at least 3 orders of magnitude more lightning in Tihany's conjugate region compared to that of Dunedin. Furthermore, whereas Tihany whistlers are generally observed at night, consistent with historical observations, Dunedin whistlers occur predominantly during the day. This paper aims to resolve two paradoxes regarding whistler occurrence at Dunedin: (i) an observation rate which is at variance with conjugate lightning activity, and (ii) a diurnal occurrence peak during daylight. The technique developed by Collier et al. (2009) is used to diagnose the location of the source lightning for Dunedin whistlers. It is found that the majority of the causative strokes occur within a region extending down the west coast of Central America.

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Observations on the Propagation Constant of the EarthIonosphere Waveguide in the Frequency Band 8 c/s to 16 kc/s

Cited by 60 publications

References 31 publications

Low-Latitude VLF Hiss Associated with the Severe Magnetic Storm on October 19-21, 1989.

Low-Latitude VLF Hiss Associated with the Severe Magnetic Storm on October 19-21, 1989.

Gigantic jets produced by an isolated tropical thunderstorm near Réunion Island

Global lightning distribution and whistlers observed at Dunedin, New Zealand

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