Diurnal latitude variation of the location of the dayside cusp

Troitskaya, V. A.; Большакова, О В

doi:10.1016/0032-0633(77)90092-7

Cited by 24 publications

(7 citation statements)

References 2 publications

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“…In general, we find our data are consistent with the previous magnetometer studies of Bol'shakova and Troitskaya [1977] and Troitskaya and Bol'shakova [1977]. The IPCL observations of Bol'shakova and Troitskaya [1977] and Troitskaya and Bol'shakova [1977] bear a striking resemblance to the pulsations we call the boundary regions. Troitskaya [1985] uses IPCL data from the Greenland network to show that at magnetic latitudes of 77-78 deg, the nominal cusp latitude, that the distribution of IPCL occurrences is symmetric with respect to magnetic noon.…”

Section: Of Troitskaya and Bol'shakova [1977] However It Should Be supporting

confidence: 92%

ULF cusp pulsations: Diurnal variations and interplanetary magnetic field correlations with ground‐based observations

McHarg¹,

Olson²,

Newell³

1995

J. Geophys. Res.

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In this paper we establish the Pc 5 magnetic pulsation signatures of the cusp and bound,try regions for the high-latitude dayside cusp region. These signatures were determined by comparing spectrograms of the magnetic pulsations with optical observations of particle precipitation regions observed at the cusp. The ULF pulsations have a diurnal variation, and a cusp discriminant is proposed using a particular narrow-band feature in the pulsation spectrogrmns. The statistical distribution of this pattern over a 253-day period resembles the statistical cusp description using particle precipitation data from the Defense Meteorological Satellite Program (DMSP). The distribution of the ground-based cusp discriminant is found to peak 1 hour earlier than the DMSP cusp distribution. This offset is due to the interplanetary •nagnetic field (IMF) being predomin•tly negative B for the period when the data were collected. We find the diurn• variations so repeatabl• that only three •nain categories of pulsation spectra explain 86 percent of ,all data observed. We find that these categories have statistically different IMF distributions. The identification of the signatures in the magnetic spectrogrmns of the boundary regions and central cusp allows the spectrogram to be used as a "time line" that shows when the station passed under different regions of the dayside oval. Introduction Large amplitude fluctuations in the Earth's magnetic field have long been observed at higher latitudes on the daysidecompared to the observations on the nightside. Feldstein and Zaitzev [1968, p. 338] report that data taken during the IGY show the "...polar electrojet with westward current is located at • -• 65 ø midnight and at • -•76 ø midday..." The early work of Bol'shakova and Troitskaya [1977] and Troitskaya and Bol'shakova [1977] identified a latitudinal dependence on the time of maximum power of long period (3-7 min) oscillations. Bol'shakova and Troitskaya [1977] call the oscillations IPCL: long-period irregular pulsations. Troitskaya [1985] shows that at latitudes of approximately 78 deg magnetic, that the diurnal variations of the IPCL pulsations are maximized and symmetric about magnetic noon. At lower latitudes the diurnal distribution of the IPCL pulsations are asymmetric, and measuring this asymmetry at lower latidues has been proposed as a method to locate the latitude of the centroid of the cusp [Troitskaya and Bol'shakova, 1977]. Samson et al. [1971] also reported on the latitudinal dependence of long-period Pc 5 magnetic field fluctuations on the dayside. Samson et al. [1971] find that the Copyright 1995 by the American Geophysical Union. Paper number 94JA03054. 0148-0227/95/94JA-03054505.00 polarization of the magnetic field perturbation vector has a distinct variation with magnetic local time and latitude. These observations led to the field line resonance theory of Chen and Hasegawa [1974] and Southwood [1974] which were successful in describing the latitudinal and local time variations of the Pc 5 oscillations. These early obs...

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Section: Of Troitskaya and Bol'shakova [1977] However It Should Be supporting

confidence: 92%

ULF cusp pulsations: Diurnal variations and interplanetary magnetic field correlations with ground‐based observations

McHarg¹,

Olson²,

Newell³

1995

J. Geophys. Res.

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“…For more detail, see [Bolshakova et al, 1974;Troitskaya, Bolshakova, 1977Troitskaya, 1985;Klain et al, 2008]. Figure 1 presents an oscillogram of oscillations recorded at Mirny Observatory (corrected geomagnetic coordinates Φ=-76.93°, Λ=122.92°).…”

Section: Introductionmentioning

confidence: 99%

North-south asymmetry of ultra-low-frequency oscillations of Earth’s electromagnetic field

Guglielmi

Klain

Potapov

2017

Solar-Terrestrial Physics

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Abstract. In the paper, we present the result of an experimental study of north-south asymmetry of ultralowfrequency electromagnetic oscillations IPCL. This study is based on observations made at Mirny Observatory (Antarctica). IPCLs are excited in the dayside sector of the auroral oval in the range 3-10 min periods and represent one of the most powerful types of oscillations of Earth's magnetosphere. These oscillations were discovered in the 1970s during IPhE AS USSR polar expeditions organized by Prof. V.A. Troitskaya. We have shown that IPCL activity in Mirny depends on the inclination (north-south asymmetry) of interplanetary magnetic field (IMF) lines to the plane of the geomagnetic equator before the front of the magnetosphere. The result suggests a controlling exposure of IMF on the magnetospheric oscillations and gives rise to the hypothesis that IPCL are forced oscillations of a nonlinear dynamical system whose major structural elements are dayside polar cusps. The paper is dedicated to the memory of Professor V. A. Troitskaya (1917A. Troitskaya ( -2010.

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“…The amplitude in the millihertz range can be several tens of nanoteslas (Figure 8); in strong events it can easily be observed on ordinary magnetograms. Troitskaya and Bolshakova [1977] have adopted this type of pulsations, which they name IPCL (irregular pulsations in the cleft) as a diagnostic tool for determining the position of the cusp. They found that the diurnal distribution of IPCL varied with latitude in a semiregular way, such that the maximum occurrence was shifted with respect to magnetic noon as function of the distance from the cusp.…”

Section: When Compared With Recordings From Our Auroral Latitude Statmentioning

confidence: 99%

ULF/ELF waves and turbulence in the high‐latitude dayside magnetosphere

Holtet¹,

Egeland²,

Doehl³

et al. 1983

Radio Science

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The magnetospheric polar cusp has been recognized as a region of strong plasma wave activity. The paper briefly summarizes previous observations of waves in the high‐altitude cusp and the dayside magnetosheath. The main part of the work is concerned with low‐frequency waves found in and near the cusp at low altitudes (500–2000 km) and on the ground. Examining the ac electric field measurements made by polar‐orbiting satellites (mainly the DE‐2), the following groups of waves appear to be characteristic for the dayside high‐latitude magnetosphere: (1) ULF/ELF broadband noise extends from the low hertz range to approximately 1 kHz. The region of peak intensity is generally found to be consistent with the latitudinal extension of the cusp. (2) VLF hiss is found to be present in the cusp region, but generally extends outside the established projection of the cusp. (3) Narrow‐band ELF emissions, covering frequencies 200 Hz ≲f ≲ 1 kHz, are observed on the equatorward side of the cusp, in the closed field line regime. Ground‐based low‐frequency wave measurements at Λ = 75.4° show in the daytime the presence of strong micropulsation activity in the frequency range ∼ 1–100 mHz and polar ELF emissions, a narrow band of relatively unstructured noise at frequencies 300 Hz ≲ f ≲ 1 kHz. The latter is believed to correspond to the satellite‐observed narrow‐band ELF noise. The frequency range 1–7 kHz is, in general, characterized in both the satellite and ground recordings by very low emission activity in the time period ∼3 hours on either side of magnetic noon. This classification of the waves is independent of the level of magnetic disturbance. It is discussed how the characteristic appearance of the ULF/ELF noise and the narrow‐band ELF emissions can be used to localize the position of the polar cusp.

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Diurnal latitude variation of the location of the dayside cusp

Cited by 24 publications

References 2 publications

ULF cusp pulsations: Diurnal variations and interplanetary magnetic field correlations with ground‐based observations

ULF cusp pulsations: Diurnal variations and interplanetary magnetic field correlations with ground‐based observations

North-south asymmetry of ultra-low-frequency oscillations of Earth’s electromagnetic field

ULF/ELF waves and turbulence in the high‐latitude dayside magnetosphere

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