Characterization of ionospheric doppler oscillations in the Pc3–4 and Pi2 magnetic pulsation frequency range

Menk, F. W.

doi:10.1016/0032-0633(92)90169-o

Cited by 21 publications

(27 citation statements)

References 61 publications

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“…However, the experimental arrangement of DOPE, where the signal phase path is near vertical and mountains between the transmitter and receiver block the ground wave path, makes it highly unlikely that either of these e ects are responsible for the Doppler signatures observed in the DOPE experiment. In addition, the suggestion by Menk (1992) that O-X mode polarisation interference might result in a beat at ULF wave frequencies can be dismissed because at high latitudes such interference is negligible compared to that at low latitudes (e.g. Toman, 1967;Reddi and Rao, 1967) where Menk (1992) made measurements.…”

Section: Alternative Causes Of the Uncorrelated Wavesmentioning

confidence: 99%

“…Since then, short-period oscillations in the frequency of HF signals have been correlated with magnetospheric ULF pulsations measured by ground magnetometers (e.g. Jacobs and Watanabe, 1966;Klostermeyer and RoÈ ttger, 1976;Tedd et al, 1989;Menk, 1992). HF Doppler sounders o er an important experimental technique for investigating the ionospheric signatures of magnetospheric ULF waves.…”

Section: Introductionmentioning

confidence: 99%

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High-latitude HF Doppler observations of ULF waves: 2. Waves with small spatial scale sizes

Wright

Yeoman

1999

Ann. Geophys.

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Abstract. The DOPE (Doppler Pulsation Experiment) HF Doppler sounder located near Tromsù, Norway (geographic: 69.6°N 19.2°E; L = 6.3) is deployed to observe signatures, in the high-latitude ionosphere, of magnetospheric ULF waves. A type of wave has been identi®ed which exhibits no simultaneous ground magnetic signature. They can be subdivided into two classes which occur in the dawn and dusk local time sectors respectively. They generally have frequencies greater than the resonance fundamentals of local ®eld lines. It is suggested that these may be the signatures of high-m ULF waves where the ground magnetic signature has been strongly attenuated as a result of the scale size of the waves. The dawn population demonstrate similarities to a type of magnetospheric wave known as giant (Pg) pulsations which tend to be resonant at higher harmonics on magnetic ®eld lines. In contrast, the waves occurring in the dusk sector are believed to be related to the storm-time Pc5s previously reported in VHF radar data. Dst measurements support these observations by indicating that the dawn and dusk classes of waves occur respectively during geomagnetically quiet and more active intervals.

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Section: Alternative Causes Of the Uncorrelated Wavesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High-latitude HF Doppler observations of ULF waves: 2. Waves with small spatial scale sizes

Wright

Yeoman

1999

Ann. Geophys.

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“…Fenwick and Villard (1960) ®rst suggested that changes in the Earth's magnetic ®eld were associated with observed shifts in the frequency of HF radio signals. Since then, short period oscillations of HF wave signal frequency have been correlated with magnetospheric ULF pulsations (which have periods in the range 0.1 s to 600 s) measured by ground magnetometers (e.g Jacobs and Watanabe, 1966;Klostermeyer and RoÈ ttger, 1976;Menk, 1992). For a more detailed description of the Doppler technique see Georges (1967) and for a discussion on its application to observing ULF waves see Wright et al (1997).…”

Section: The High-latitude Doppler Soundermentioning

confidence: 99%

“…Whilst several previous authors (e.g. Menk, 1992;Tedd et al, 1989) have demonstrated that geomagnetic pulsations can be present without the occurrence of an observable ionospheric signature, ratio B still provides a measure of the intrinsic occurrence of the ionospheric signatures of pulsations. Ratio C is that of the number of pulsations to all observations.…”

Section: Compiling the Statistical Data Setmentioning

confidence: 99%

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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“…Since then, short-period oscillations in the frequency of HF signals have been correlated with magnetospheric ULF pulsations measured by ground magnetometers (e.g. Jacobs and Watanabe, 1966;Klostermeyer and RoÈ ttger, 1976;Tedd et al, 1989;Menk, 1992). Recently, Wright et al (1997) presented a detailed study of ULF wave signatures observed by a new sounder at high latitudes (see Sect.…”

Section: Introductionmentioning

confidence: 97%

A comparison of EISCAT and HF Doppler observations of a ULF wave

Wright¹,

Yeoman²,

Davies³

1998

Ann Geophysicae

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Abstract. Since the middle of 1995, an HF Doppler sounder has been running almost continuously in northern Norway, with the receiver at Ramfjordmoen and the transmitter at Seljelvnes. Concurrent operation of the EISCAT UHF radar in common programme (CP-1) mode has made it possible to study the ionospheric signature of a magnetospheric ULF wave. These are the ®rst results of such wave signatures observed simultaneously in both instruments. It has been demonstrated that the observed Doppler signature was mainly due to the vertical bulk motion of the ionosphere caused by the electric ®eld perturbation of the ULF wave and the ®rst direct observational con®rmation of a numerical simulation has been achieved. The wave, which was AlfveÂ nic in nature, was detected by the instruments 8°equatorward of the broad resonance region. The implications for the deduced wave modes in the ionosphere and the mechanism producing the HF Doppler variations are discussed.

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Characterization of ionospheric doppler oscillations in the Pc3–4 and Pi2 magnetic pulsation frequency range

Cited by 21 publications

References 61 publications

High-latitude HF Doppler observations of ULF waves: 2. Waves with small spatial scale sizes

High-latitude HF Doppler observations of ULF waves: 2. Waves with small spatial scale sizes

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

A comparison of EISCAT and HF Doppler observations of a ULF wave

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