Periodic and quasiperiodic ELF/VLF emissions observed by an array of Antarctic stations

Smith, A. J.; Engebretson, M. J.; Klatt, E.; Inan, U. S.; Arnoldy, R. L.; Fukunishi, H.

doi:10.1029/98ja01955

Cited by 49 publications

(68 citation statements)

References 23 publications

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“…More recently, Smith et al [1998] used data from South Pole, Halley, and the P2 and P3 AGOs (Automated Geophysical Observatories), displayed in the form of differenced FFT spectrograms, to explore the relations between QP events and PE events. Among other findings, this study found a strong association between PE events and the simultaneous appearance of type II QPs.…”

Section: Introductionmentioning

confidence: 99%

Latitudinal and seasonal variations of quasiperiodic and periodic VLF emissions in the outer magnetosphere

et al. 2004

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[1] We have analyzed ELF-VLF receiver and search coil magnetometer data from five Antarctic stations from 1998 and 1999 to study quasiperiodic emissions (QPs) and periodic emissions (PEs), which occur as ULF-range modulations of ELF-VLF signals between 0.5 kHz and $4 kHz. QPs are modulated at frequencies of $20-50 mHz, and PEs are modulated at frequencies of $200-500 mHz. The stations used covered a range of magnetic latitudes from À62°(Halley) to À74°(South Pole Station); three automated geophysical observatories (AGOs) were located at intermediate latitudes.Consistent with earlier studies, most QPs were observed with magnetic pulsations of identical period in the Pc3 range (type I QPs). Of those QPs not observed with simultaneous magnetic pulsations (type II QPs), nearly all were accompanied by PEs. Type I QPs, PEs, and events during which both appeared together (QPPEs) were found to have different latitudinal, seasonal, and diurnal occurrence patterns: QPs of both types were more likely to occur between À65°and À70°magnetic latitude, while PEs occurred more often around À60°magnetic latitude. QPs were more common during the months of October though March, while PEs were more common during the months of May through September. QPs, whether with or without simultaneous PEs or magnetic pulsations, were predominantly a dayside phenomenon, with a broad maximum near local noon. The occurrence of QPs unaccompanied by PEs was restricted to the dayside, however, while a small number of QPPEs appeared even during nighttime hours. PEs, on the other hand, could be seen at all local times, but with latitudinally dependent diurnal patterns. Most higher-latitude QPs were type I events (observed with magnetic pulsations), while type II QP events (without simultaneous magnetic pulsations) occurred relatively more often at lower latitudes. A case study from 1 August 1999 using wideband data from South Pole and Halley provides evidence of a transition from echoing whistler activity to PE activity and then to QP activity and suggests a causal relationship.INDEX TERMS: 2772 Magnetospheric Physics: Plasma waves and instabilities; 2752 Magnetospheric Physics: MHD waves and instabilities; 2483 Ionosphere: Wave/particle interactions; 7867 Space Plasma Physics: Wave/particle interactions;

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Section: Introductionmentioning

confidence: 99%

Latitudinal and seasonal variations of quasiperiodic and periodic VLF emissions in the outer magnetosphere

et al. 2004

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“…Clearly, the pulses in pulsing VLF hiss emission are mainly undispersed band limited noise consisting of multitude of rising tones of burst type and dispersed signals which on some occasions consist of falling and rising tones of hyperbolic shape. Pulsing VLF hiss emissions reported in this paper both occurred in the late afternoon and peak around 15:00 IST local time during quiet and disturbed days, whereas the ELF pulsing hiss emission observed on GEOS-2 occurred during night-time associated with sub-storms and pulsating aurora (Sazhin and Hayakawa 1994;Smith et al 1998). Pulsing VLF hiss emissions with lower cut-off frequency of 2.5 kHz presented in this paper are observed above the waveguide cut-off frequency.…”

Section: Resultsmentioning

confidence: 36%

“…Attempts had been made to record such type of emissions at other Indian stations and Singh et al (2005) have reported observation of pulsing hiss at Varanasi only in night-times. The observation of pulsing hiss emissions at the ground station Jammu during daytime is rare in the sense that most of the reported observations are mainly from mid/high latitudes (Ward et al 1982;Smith et al 1998).…”

Section: Resultsmentioning

confidence: 84%

“…Hiss-type emissions have been reported which show a degree of periodicity of somewhat shorter periods (from fractions of a second to several seconds), such as 'hisslers' (Ungstrup and Carpenter 1974;Singh et al 2004) and 'pulsing hiss' (Ward et al 1982;Singh et al 2005). These are largely a night phenomenon associated with sub-storm and pulsating aurora respectively (Smith et al 1998).…”

Section: Introductionmentioning

confidence: 98%

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Quasi-periodic VLF emissions observed during daytime at a low latitude Indian ground station Jammu

Singh

Singh²,

Patel³

et al. 2009

J Earth Syst Sci

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This paper reports quasi-periodic pulsing hiss emissions recorded during daytime in the frequency range of 50 Hz-15 kHz at low latitude station Jammu (geomag. lat. = 22 • 26 N; L = 1.17). It is noted that pulsing VLF emissions are a rare phenomena at low latitudes. The various spectrograms of pulsing VLF hiss emissions presented in this paper clearly show band limited spectrums regularly pulsing with almost equal period of the order of few seconds in the frequency range of ∼ 3-8 kHz. Generation and propagation mechanism of these emissions are briefly discussed.

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“…Comparing the mid latitude whistler data and Pc3 pulsation data, Vero et al (1997) suggested that whistler ducts and geomagnetic field line shells may be connected with each other. Smith et al (1998) have also reported amplitude modulations of periodic and quasiperiodic VLF emissions at high latitudes in two period ranges 4-6 s and 10-60 s respectively. Recently, Marcz and Vero (2002) have analyzed micropulsations and whistler data recorded at mid latitudes and concluded that certain structures in the magnetosphere such as field line shells (Pc3 pulsations), whistler ducts, paths for wave packets (Pc1 pulsations) and particle precipitation (ionospheric absorption and Pc1) appear together suggesting some link between them.…”

Section: Introductionmentioning

confidence: 87%

Observation of pulsing hiss at low latitudes

Singh

Patel

Singh

et al. 2005

Journal of Atmospheric and Solar-Terrestrial Physics

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Periodic and quasiperiodic ELF/VLF emissions observed by an array of Antarctic stations

Cited by 49 publications

References 23 publications

Latitudinal and seasonal variations of quasiperiodic and periodic VLF emissions in the outer magnetosphere

Latitudinal and seasonal variations of quasiperiodic and periodic VLF emissions in the outer magnetosphere

Quasi-periodic VLF emissions observed during daytime at a low latitude Indian ground station Jammu

Observation of pulsing hiss at low latitudes

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