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Lalmani,; Babu, Madhu Kaul; Kumar, Rajou; Singh, R. P.; Singh, Krishna Kumar

doi:10.1023/a:1018959818988

Cited by 4 publications

(2 citation statements)

References 22 publications

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“…The wave normal at the entrance into the waveguide is such that they propagated towards the equator and are received at our low latitude ground station Jammu. The upper boundary frequency (UBF) method as developed by Smirnova [15] has been generally used to find out the location of VLF/ ELF emissions observed at low latitude ground stations [16][17][18][19]. The upper boundary frequencies of the ground observed VLF/ELF emissions are determined on the assumption of dipolar geomagnetic field configuration, by the half electron gyrofrequency in the generation region irrespective of the observation station.…”

Section: Observational Results and Discussionmentioning

confidence: 99%

Characteristics of nighttime VLF/ELF emissions with frequency drift and estimation of the large-scale electric field from the frequency drift observed at a low latitude Indian ground station, Jammu

et al. 2010

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Characteristics of nighttime VLF/ELF emissions are examined on the basis of the data obtained at our low latitude ground station Jammu (geomagnetic latitude, 22°26¢ N; L = 1.17), India during our VLF/ELF campaign. From the detailed analysis of a huge amount of acquired VLF/ELF data at Jammu we have found three remarkable events which clearly exhibit a rise in their frequency in pre and past midnight sectors during magnetically quiet and substorm periods. Our analysis shows that the frequency drift in VLF/ELF emissions seems to be a rare phenomenon at low latitudes during magnetically quiet and substorm periods in pre and post midnight sectors. This property of temporal frequency drift (regular frequency increases with time) in VLF/ELF emissions observed at our station Jammu are interpreted in terms of a quasi-linear electron cyclotron instability model for wave excitation. The initial frequency increase is believed to be due to a combind effect of L-shell drift of energetic electrons. Further, the frequency drifts in VLF/ELF emissions observed at Jammu have been used to estimate the large scale electric field during quiet and substorm periods in pre and post midnight sectors. This investigation would be most useful for the study of the wave-particle interaction processes, magnetospheric plasma structure and particle dynamics, especially during quiet periods in premidnight sector at low latitudes.Keywords : VLF/ELF emissions, quiet and substorm periods, electric field, quasi-linear electron cyclotron instability, wave particle interaction, magnetospheric plasma.

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Section: Observational Results and Discussionmentioning

confidence: 99%

Characteristics of nighttime VLF/ELF emissions with frequency drift and estimation of the large-scale electric field from the frequency drift observed at a low latitude Indian ground station, Jammu

et al. 2010

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“…Poynting vector for V-shaped hiss is downward along the field lines whereas V-shaped saucer emissions have upward wave normal direction [46]. Recently, Lalmani et al [49] reported VLF saucer emissions from the low latitude ground station Jammu.…”

Section: Experimental Datamentioning

confidence: 99%

Hiss emissions during quiet and disturbed periods

Singh

2002

Pramana - J Phys

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The characteristic features of VLF hiss emissions during quiet and disturbed conditions observed at ground stations and on-board satellites are summarized. The increased intensity of the hiss emissions during magnetic storm period is explained by considering the enhanced flux of energetic electrons during magnetic storm period. The generation and propagation mechanism of VLF hiss are also briefly discussed.

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ESD whistlers from local Thunderstorms observed at Srinagar (L = 1.28) – First observation from Low Latitudes

Singh

Sheik

2015

JAE

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Abstract:This paper reports the first observation of extremely small dispersion (ESD) whistlers from thunderstorms recorded during magnetic storm period at a low latitude ground station Srinagar (geomag. lat., 24 0 10' N; L=1.28). ESD whistlers with dispersion varying from 4-5 sec ½ surprisingly in large numbers were recorded on 06 April, 2011 at Srinagar during local thunderstorm period in the daytime afternoon. Such type of daytime ESD whistlers from local thunderstorm recorded during magnetic storm period at Srinagar has never been reported from any of the low latitude ground stations and is the first observation from low latitudes. Results of the study of the characteristics of daytime ESD whistlers from local thunderstorms observed at Srinagar shows that these whistlers are ducted whistlers and are found to obey perfectly the Eckersley law. Since the dispersion of these daytime ESD whistlers are found in the extremely small range of the order of 5 sec ½ which clearly shows that these whistlers have propagated over an extremely small path along the ducted field lines. It is proposed that daytime ESD whistlers from local thunderstorms recorded at Srinagar are the VLF waves radiated from the return stroke of lightning discharge present in local thunderstorms penetrated the ionosphere in waveguide mode and then they propagated to the other hemisphere along the geomagnetic field line of latitude ~ 5 0 in whistler duct formed by the local thunderstorm electrostatic electric fields. After reaching the opposite hemisphere, these whistler waves again traverse in the waveguide mode to reach the observing station Srinagar. The generation and propagation mechanisms of these ESD whistlers observed during local thunderstorms are discussed.

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Untitled

Cited by 4 publications

References 22 publications

Characteristics of nighttime VLF/ELF emissions with frequency drift and estimation of the large-scale electric field from the frequency drift observed at a low latitude Indian ground station, Jammu

Characteristics of nighttime VLF/ELF emissions with frequency drift and estimation of the large-scale electric field from the frequency drift observed at a low latitude Indian ground station, Jammu

Hiss emissions during quiet and disturbed periods

ESD whistlers from local Thunderstorms observed at Srinagar (L = 1.28) – First observation from Low Latitudes

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