Diagnostics of the magnetosphere using multipoint measurements of ULF-waves

Troitskaya, V. A.; Большакова, О В

doi:10.1016/0273-1177(88)90155-x

Cited by 36 publications

(27 citation statements)

References 13 publications

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“…This result con®rms that in the polar cap solar wind controlled pulsations can be observed also during night-time hours (Engebtretson et al, 1989), supporting the idea of an additional high latitude entry of the upstream ULF wave energy (Engebretson et al, 1991). In this sense we found that, in agreement with previous results (review by Troitskaya and Bolshakova, 1988), both at low and high latitude the dominant wave frequency depends on the strength of the IMF according to the relation f (mHz) $ 6 B (nT).…”

Section: Summary and Discussionsupporting

confidence: 83%

“…In this sense, an empirical relationship between the dominant frequency of the dayside Pc3 pulsations (20 mHz < f < 100 mHz) and the strength, B, of the interplanetary magnetic ®eld (hereafter IMF) has been found in several investigations [f(mHz) $ 6B (nT), review by Troitskaya and Bolshakova, 1988]. This relationship has been interpreted as an important argument in favor of the model predicting that these pulsations could be directly related to ion cyclotron upstream waves generated in the foreshock region along IMF lines connected to the quasi-parallel bow shock (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Pc3 pulsations during variable IMF conditions

et al. 1999

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Abstract. Pc3 geomagnetic ®eld¯uctuations detected at low latitude (L'Aquila, Italy) during the passage of a high velocity solar wind stream, characterized by variable interplanetary magnetic ®eld conditions, are analyzed. Higher frequency resonant¯uctuations and lower frequency phenomena are simultaneously observed; the intermittent appearance and the variable frequency of the longer period modes can be well interpreted in terms of the variable IMF elements; moreover their polarization characteristics are consistent with an origin related to external waves propagating in antisunward direction. A comparison with simultaneous observations performed at Terra Nova Bay (Antarctica) provides additional evidence for a clear relationship between the IMF and Pc3 pulsations also at very high latitudes.

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Section: Summary and Discussionsupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Pc3 pulsations during variable IMF conditions

et al. 1999

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“…An important argument in favor of the upstream wave source is the generally observed linear relation between the frequency of ground pulsations and the IMF strength, i.e. f [mHz] ∼6·B I MF [nT] (Troitskaya and Bolshakova, 1988). In addition, the IMF orientation also plays a significant role in that ground pulsations occur more frequently when the cone angle (the angle θ XB between the IMF and the Sun-Earth line) is small, suggesting a direct transmission of waves from the subsolar bow shock (Russell et al, 1983).…”

Section: The Temporal Pattern Of Pcwave Activitymentioning

confidence: 99%

ULF fluctuations of the geomagnetic field and ionospheric sounding measurements at low latitudes during the first CAWSES campaign

Villante¹,

Vellante²,

Francia³

et al. 2006

Ann. Geophys.

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Abstract.We present an analysis of ULF geomagnetic field fluctuations at low latitudes during the first CAWSES campaign (29 March-3 April 2004). During the whole campaign, mainly in the prenoon sector, a moderate Pc3-4 pulsation activity is observed, clearly related to interplanetary upstream waves. On 3 April, in correspondence to the Earth's arrival of a coronal mass ejection, two SIs are observed whose waveforms are indicative of a contribution of the high-latitude ionospheric currents to the low-latitude ground field. During the following geomagnetic storm, low frequency (Pc5) waves are observed at discrete frequencies. Their correspondence with the same frequencies detected in the radial components of the interplanetary magnetic field and solar wind speed suggests that Alfvénic solar wind fluctuations may act as direct drivers of magnetospheric fluctuations. A cross-phase analysis, using different pairs of stations, is also presented for identifying field line resonant frequencies and monitoring changes in plasmaspheric mass density. Lastly, an analysis of ionospheric vertical soundings, measured at the Rome ionosonde station (41.8 • N, 12.5 • E), and vertical TEC measurements deduced from GPS signals within an European network shows the relation between the ULF resonances in the inner magnetosphere and thermal plasma density variations during geomagnetically quiet conditions, in contrast to various storm phases at the end of the CAWSES campaign.

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“…In the mid-frequency range (7-100 mHz, Pc3-4), pulsations are mainly due to the transmission into the magnetosphere of interplanetary upstream waves (Greenstadt et al, 1980) generated through ion-cyclotron instability by protons reflected off the bow shock along the interplanetary magnetic field (IMF) lines; given the spiral orientation of the IMF and the frequency dependence on the IMF strength (f(mHz) ∼6 B (nT); Troitskaya and Bolshakova, 1988), the resulting waves are mostly observed in the morning side at frequencies in the Pc3 range. The Kelvin-Helmholtz instability might play a role in the amplification of these waves, as they are convected and transmitted through the magnetopause (Engebretson et al, 1986).…”

Section: Introductionmentioning

confidence: 99%