A statistical study of dayside magnetospheric electric field fluctuations with periods between 150 and 600 s

Junginger, H.; Geiger, G.; Haerendel, G.; Melzner, Frank; Amata, E.; Higel, B.

doi:10.1029/ja089ia07p05495

Cited by 52 publications

(42 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1 do not demonstrate a clear peak at the fundamental harmonic of field line resonances that is consistent with earlier studies at the geostationary orbit. Junginger et al (1984) presented mean electric and magnetic field PSDs calculated from 6 months of GEOS-2 data showing a broad peak in the electric field PSD around 3 mHz (the fundamental harmonic of field line resonances) with no clear peak in the magnetic field PSD. Recent studies of the magnetic ULF PSDs using GOES data (e.g.…”

Section: Discussion and Summarymentioning

confidence: 99%

The influence of solar wind variability on magnetospheric ULF wave power

Pokhotelov¹,

Rae²,

Murphy

et al. 2015

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. Magnetospheric ultra-low frequency (ULF) oscillations in the Pc 4-5 frequency range play an important role in the dynamics of Earth's radiation belts, both by enhancing the radial diffusion through incoherent interactions and through the coherent drift-resonant interactions with trapped radiation belt electrons. The statistical distributions of magnetospheric ULF wave power are known to be strongly dependent on solar wind parameters such as solar wind speed and interplanetary magnetic field (IMF) orientation. Statistical characterisation of ULF wave power in the magnetosphere traditionally relies on average solar wind-IMF conditions over a specific time period. In this brief report, we perform an alternative characterisation of the solar wind influence on magnetospheric ULF wave activity through the characterisation of the solar wind driver by its variability using the standard deviation of solar wind parameters rather than a simple time average. We present a statistical study of nearly one solar cycle (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)) of geosynchronous observations of magnetic ULF wave power and find that there is significant variation in ULF wave powers as a function of the dynamic properties of the solar wind. In particular, we find that the variability in IMF vector, rather than variabilities in other parameters (solar wind density, bulk velocity and ion temperature), plays the strongest role in controlling geosynchronous ULF power. We conclude that, although time-averaged bulk properties of the solar wind are a key factor in driving ULF powers in the magnetosphere, the solar wind variability can be an important contributor as well. This highlights the potential importance of including solar wind variability especially in studies of ULF wave dynamics in order to assess the efficiency of solar wind-magnetosphere coupling.

show abstract

Section: Discussion and Summarymentioning

confidence: 99%

The influence of solar wind variability on magnetospheric ULF wave power

Pokhotelov¹,

Rae²,

Murphy

et al. 2015

Ann. Geophys.

View full text Add to dashboard Cite

show abstract

“…Although its amplitude is small, it is prominent in regions closer to the Earth during quiet geomagnetic activity. Typically, the AC component of electric fields are reported as Pc 5 pulsations [e.g., Junginger et al , 1984] and irregular oscillations [e.g., Quinn et al , 1999]. These oscillating components are known to be comparable in size to the DC component, so they may have an important effect on the transport of the plasmas.…”

Section: Introductionmentioning

confidence: 99%

Electric field measurements in the inner magnetosphere by Cluster EDI

et al. 2003

View full text Add to dashboard Cite

[1] We report electric field measurements in the inner magnetosphere from the Electron Drift Instrument (EDI) on Cluster at distances of 4 < L < 10. The data used in this study span more than 1 year so that all local times are covered. Both components of the electric field perpendicular to the ambient magnetic field are mapped into the equatorial plane with the magnetic field model of Tsyganenko and Stern [1996]. Average values and standard deviations are sorted by the polarity of the B Z component of the interplanetary magnetic field (IMF). Average Kp values for both B Z polarities are 1.45 (B Z > 0) and 2.45 (B Z < 0). These electric fields are discussed in terms of their sources such as the ionospheric dynamo and the solar wind-magnetosphere interaction. We also quantify the electric field as follows: the average shielding parameter g [Volland, 1973;Stern, 1975] is $2, although the value for southward IMF is smaller than the value for northward IMF. The parameter g is larger on the duskside than in the dawn sector. The average rate of sunward transport of magnetic flux, equivalent to the duskward electric field, is estimated as 0.32 mV/m for southward IMF. Finally, fluctuations tend to be larger than the DC component around the stagnation point, which could lead to outflow of plasmaspheric material.

show abstract

“…The low-frequency peak appears centered in the 1-3mHz band and the high frequency peak in the 3-6mHz band. Although KOKUBUN (1985) cautioned that the occurrence probability of electric oscillations is different from those of magnetic pulsations on the ground and at synchronous altitude, the double-peak feature in the histograms in JUNGINGER et al (1984) show remarkable resemblance to the ground data presented here. Kokubun also noted that the discrepancy among the characteristics of Pc5 obtained in the analysis of magnetic field and electric field data has not yet been understood.…”

Section: Presentation Of the Datamentioning

confidence: 67%

“…JUNGINGER et al (1984) used 186 days of electric field data from the European Space Agency's geostationary satellite GEOS 2 to study pulsations in the Pc5 frequency range. The low-frequency peak appears centered in the 1-3mHz band and the high frequency peak in the 3-6mHz band.…”

Section: Presentation Of the Datamentioning

confidence: 99%

A possible classification of Pc5 geomagnetic pulsations into two sub-groups(Pc5A and Pc5B) based on spectral structure.

Lam

1989

J. geomagn. geoelec

View full text Add to dashboard Cite

Ground magnetic data recorded in the auroral zone station at Fort Churchill, Canada (FCC) during 1985 were used to study the spectral content of Pc5 magnetic pulsations. It was found that spectral peaks tend to group into two separate bands of 1-3mHz and 3-6mHz. The power in both bands appears to be linearly related to global planetary geomagnetic activity as represented by the Ap index. While pulsations in both bands show a 27-day recurrence tendency, only intense pulsations in the low frequency band (1-3mHz) seem to recur in the morning a few days after an initial enhancement. On the other hand, pulsations in the high frequency band (3-6mHz) always have low amplitudes in the afternoon. In general, the low frequency band activity is more intense than the high frequency band activity . It is suggested that Pc5 pulsations can be classified into two sub-groups, with pulsations in the low frequency band of 1-3mHz classified as Pc5A and those in the high frequency band of 3-6mHz classified as Pc5B. Probably, Pc5A is associated with the "ringing" of the large-scale three-dimensional magnetospheric and ionospheric current systems and Pc5B is due to field line resonance. This classification scheme would provide a convenient mean of expressing and recognizing the frequency content of Pc5 events.

show abstract

A statistical study of dayside magnetospheric electric field fluctuations with periods between 150 and 600 s

Cited by 52 publications

References 45 publications

The influence of solar wind variability on magnetospheric ULF wave power

The influence of solar wind variability on magnetospheric ULF wave power

Electric field measurements in the inner magnetosphere by Cluster EDI

A possible classification of Pc5 geomagnetic pulsations into two sub-groups(Pc5A and Pc5B) based on spectral structure.

Contact Info

Product

Resources

About