On the quiet-time Pc 5 pulsation events (Spacequakes)

Gupta, Jagdish C.; Niblett, E. R.

doi:10.1016/0032-0633(79)90043-6

Cited by 12 publications

(18 citation statements)

References 38 publications

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“…It has been suggested that the Kelvin-Helmholtz instability on the dawn and dusk¯anks of the magnetopause is the driving mechanism for this type of wave. This suggestion is supported by ground-based observations since the same bimodal asymmetrical occurrence distribution over local time is observed by high-latitude magnetometer stations (Gupta, 1973;Rao and Gupta, 1978;Gupta and Niblett, 1979;Ziesolleck and McDiarmid, 1995), and by the STARE VHF radar (Walker and Greenwald, 1981).…”

Section: Introductionsupporting

confidence: 71%

“…Gupta and Niblett (1979) established that their quiet time events generally occurred at K p £ 3 (A p £ 15) at all stations. Gupta (1973) found that the Pc5 events recorded over one year at high latitude had an occurrence rate which appeared to increase linearly with K p up to 5 and with SK p (the sum of K p index over the day) up to around 37.…”

Section: Introductionmentioning

confidence: 89%

“…Gupta, 1973;Rao and Gupta, 1978;Gupta and Niblett, 1979;Ziesolleck and McDiarmid, 1995) and coherent VHF auroral radars such as the Scandinavian Twin Auroral Radar Experiment (STARE; Greenwald et al, 1978) (e.g. Walker and Greenwald, 1981) and the Sweden And Britain Radar-auroral Experiment (SA-BRE; Nielsen et al, 1983) (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…This author reported that more observations of Pc5s occurred in the summer months than in the winter. However, subsequent studies by Gupta and Niblett (1979) report the seasonal variations in what they describe as``quiet time Pc5s'' which are ®eld line resonances. Using a few high-latitude Canadian observatories they determined, from an 11 year data set, that most events occurred between December and March of each year and a that a minimum of occurrence appeared around May±July.…”

Section: Introductionmentioning

confidence: 99%

“…Gupta and Niblett (1979) examined 11 years of data from high-latitude magnetometer stations and concluded that if a relationship does exist, then it is a complex one. The number of events did increase with sunspot number but there were large perturbations from this trend.…”

Section: Introductionmentioning

confidence: 99%

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ULF wave occurrence statistics in a high-latitude HF Doppler sounder

1999

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Abstract. Ultra low frequency (ULF) wave activity in the high-latitude ionosphere has been observed by a high frequency (HF) Doppler sounder located at Tromsù, Norway (69.7°N, 19.2°E geographic coordinates). A statistical study of the occurrence of these waves has been undertaken from data collected between 1979 and 1984. The diurnal, seasonal, solar cycle and geomagnetic activity variations in occurrence have been investigated. The ®ndings demonstrate that the ability of the sounder to detect ULF wave signatures maximises at the equinoxes and that there is a peak in occurrence in the morning sector. The occurrence rate is fairly insensitive to changes associated with the solar cycle but increases with the level of geomagnetic activity. As a result, it has been possible to characterise the way in which prevailing ionospheric and magnetospheric conditions a ect such observations of ULF waves.

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Section: Introductionsupporting

confidence: 71%

Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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ULF wave occurrence statistics in a high-latitude HF Doppler sounder

1999

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ULF wave occurrence statistics in a high-latitude HF Doppler sounder

1999

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Ultra low frequency (ULF) wave activity in the high-latitude ionosphere has been observed by a high frequency (HF) Doppler sounder located at Tromsù, Norway (69.7°N, 19.2°E geographic coordinates). A statistical study of the occurrence of these waves has been undertaken from data collected between 1979 and 1984. The diurnal, seasonal, solar cycle and geomagnetic activity variations in occurrence have been investigated. The ®ndings demonstrate that the ability of the sounder to detect ULF wave signatures maximises at the equinoxes and that there is a peak in occurrence in the morning sector. The occurrence rate is fairly insensitive to changes associated with the solar cycle but increases with the level of geomagnetic activity. As a result, it has been possible to characterise the way in which prevailing ionospheric and magnetospheric conditions aect such observations of ULF waves.

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Some characteristics of high-latitude substorm

Loomer

Gupta

1980

Journal of Atmospheric and Terrestrial Physics

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On the quiet-time Pc 5 pulsation events (Spacequakes)

Cited by 12 publications

References 38 publications

ULF wave occurrence statistics in a high-latitude HF Doppler sounder

ULF wave occurrence statistics in a high-latitude HF Doppler sounder

ULF wave occurrence statistics in a high-latitude HF Doppler sounder

Some characteristics of high-latitude substorm

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