Periodic magnetopause oscillations observed with the GOES satellites on March 24, 1991

Cahill, L. J.; Winckler, J. R.

doi:10.1029/92ja00433

Cited by 38 publications

(31 citation statements)

References 23 publications

(25 reference statements)

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“…However, statistical studies by ground‐based magnetometers of Pc‐5 waves indicate that the preponderance of ULF wave activity occurs on the flanks, with perhaps more activity in the dawn sector [ Anderson et al , 1990; Ruohoniemi et al , 1991]. Further, if the ULF wave activity is a result of flow instabilities along the flanks [ Cahill and Winckler , 1992; Mann et al , 1999; Mathie and Mann , 2000b], one would expect the wave power to be directed generally tailward, i.e., propagating eastward in the dusk sector and westward in the dawn sector. How would electron acceleration be affected in each case?…”

Section: Local Time and Propagation Effectsmentioning

confidence: 99%

“…Ground observations suggest that Pc‐5 ULF oscillations are most prevalent in the dawn sector of the magnetosphere [ Anderson et al , 1990; Ruohoniemi et al , 1991; Glassmeier and Stellmacher , 2000], and have a higher occurrence rate during periods of high solar wind speed [ Kokubun et al , 1989; Engebretson et al , 1998]. The source of wave power driving Pc‐5 oscillations has been speculated to be either through Kelvin‐Helmholtz waves generated by the flow of the solar wind past the magnetospheric boundary surface [ Cahill and Winckler , 1992; Mann et al , 1999], or through variations in the solar wind pressure propagating as wave energy into the magnetosphere [ Lysak and Lee , 1992]. In a study examining phase velocities of magnetospheric ULF waves, Mathie and Mann [2000b] found that morning‐sector waves during high speed solar wind events ( v sw ≃ 500 km/s) were likely driven by magnetopause flow instabilities, whereas during lower solar wind velocities observed ULF pulsations were likely a result of the impulsive action of the solar wind.…”

Section: Introductionmentioning

confidence: 99%

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Resonant acceleration and diffusion of outer zone electrons in an asymmetric geomagnetic field

2003

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[1] The outer zone radiation belt consists of energetic electrons drifting in closed orbits encircling the Earth between $3 and 7 R E . Electron fluxes in the outer belt show a strong correlation with solar and magnetospheric activity, generally increasing during geomagnetic storms with associated high solar wind speeds, and increasing in the presence of magnetospheric ULF waves in the Pc-5 frequency range. In this paper, we examine the influence of Pc-5 ULF waves on energetic electrons drifting in an asymmetric, compressed dipole and find that such particles may be efficiently accelerated through a drift-resonant interaction with the waves. We find that the efficiency of this acceleration increases with increasing magnetospheric distortion (such as may be attributed to increased solar wind pressure associated with high solar wind speeds) and with increasing ULF wave activity. A preponderance of ULF power in the dawn and dusk flanks is shown to be consistent with the proposed acceleration mechanism. Under a continuum of wave modes and frequencies, we find that the drift resonant acceleration process leads to additional modes of radial diffusion in the outer belts, with timescales that may be appropriate to those observed during geomagnetic storms.

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Section: Local Time and Propagation Effectsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Resonant acceleration and diffusion of outer zone electrons in an asymmetric geomagnetic field

2003

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“…In this regard, it has been shown for example that solar wind speed (V sw ) correlates with ULF power in the Pc3 to Pc5 frequency range (1.7 to 100 mHz) [e.g., Greenstadt et al, 1979;Mathie and Mann, 2000;Pahud et al, 2009;Simms et al, 2010;Rae et al, 2012], with a likely physical mechanism being the generation of shear flow instabilities along the magnetopause [Cahill and Winckler, 1992;Mann et al, 1999;Mathie and Mann, 2000]. Solar wind dynamic pressure changes (P dyn ) have also been found to be correlated with ULF wave excitation [e.g., Kepko et al, 2002;Takahashi and Ukhorskiy, 2007;Kessel, 2008], possibly due to the generation of compressional waves that transmit their energy to field line resonances in the inner magnetosphere [Kivelson and Southwood, 1988;Lysak and Lee, 1992;Mann et al, 1995;Hartinger et al, 2011].…”

Section: Introductionmentioning

confidence: 99%

Accurately specifying storm‐time ULF wave radial diffusion in the radiation belts

Dimitrakoudis

Mann

Balasis

et al. 2015

Geophysical Research Letters

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Ultralow frequency (ULF) waves can contribute to the transport, acceleration, and loss of electrons in the radiation belts through inward and outward diffusion. However, the most appropriate parameters to use to specify the ULF wave diffusion rates are unknown. Empirical representations of diffusion coefficients often use Kp; however, specifications using ULF wave power offer an improved physics‐based approach. We use 11 years of ground‐based magnetometer array measurements to statistically parameterize the ULF wave power with Kp, solar wind speed, solar wind dynamic pressure, and Dst. We find that Kp is the best single parameter to specify the statistical ULF wave power driving radial diffusion. Significantly, remarkable high energy tails exist in the ULF wave power distributions when expressed as a function of Dst. Two‐parameter ULF wave power specifications using Dst as well as Kp provide a better statistical representation of storm‐time radial diffusion than any single variable alone.

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“…To date, several studies on the event of 24 March 1991 have been reported in the literature (Cahill and Winckler 1992;Yumoto et al 1992;Fujitani et al 1993;Liu et al 1993;Reddy et al 1994;Trivedi et al 1997;Schott et al 1998). Most of these studies focused on a local investigation of the characteristics and driving causes of the pulsations through an analysis of the data obtained solely from ground stations or from satellites.…”

Section: Introductionmentioning

confidence: 99%

“…Most of these ULF waves are categorized as the Pc 5 waves (1.7 < f < 6.7 mHz). The ground-based and satellite observations of the Pc 5 waves have been reported for a few decades (e.g., Brown et al 1968;Barfield and McPherron 1972;Takahashi et al 1986Takahashi et al , 1987Takahashi et al , 1990Cahill and Winckler 1992;Kepko et al 2002;Kepko and Spence 2003). Generally speaking, according to their dominant variations, these waves are categorized as compressional and transverse Pc 5 waves.…”

Section: Introductionmentioning

confidence: 99%

Global Ultra-Low-Frequency Geomagnetic Pulsations Associated with the March 24, 1991 Geomagnetic Storm

Chen

Liu²

2008

Terr. Atmos. Ocean. Sci.

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On 24 March 1991, global ultra-low-frequency (ULF) pulsations (1.1 -3.3 mHz) observed in the magnetosphere as well as on the ground were studied via analyzing magnetic field data obtained from a global network, comprising ground-based observatories and geosynchronous satellites. In the magnetosphere, the compressional and transverse components of the magnetic fields recorded at two satellites, GOES 6 and GOES 7, showed dominant fluctuations when they were in the vicinity of the noon sector, whereas the transverse fluctuations became dominant when they were at the dawn side. Similarly, on the ground, the H and D components had major fluctuations along with an increase in amplitude from low to high geomagnetic latitudes. In addition, the amplitude of the ULF pulsation was enhanced at the dawn and dusk sides. The geomagnetic pulsations propagated anti-sunward and were of counterclockwise and clockwise elliptical polarizations at the dawn and dusk sides respectively. The counterclockwise elliptical polarization reversed to a clockwise elliptical polarization at geomagnetic local noon and linear polarization was observed during the reversal. It appears that the analysis of the global network data not only provided us with a study of the characteristics of the waves in the magnetosphere and on the ground but also provided us with correlations between the geosynchronous and ground observations, which should be essential to the determination of possible mechanisms of this storm-related wave event.

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Periodic magnetopause oscillations observed with the GOES satellites on March 24, 1991

Cited by 38 publications

References 23 publications

Resonant acceleration and diffusion of outer zone electrons in an asymmetric geomagnetic field

Resonant acceleration and diffusion of outer zone electrons in an asymmetric geomagnetic field

Accurately specifying storm‐time ULF wave radial diffusion in the radiation belts

Global Ultra-Low-Frequency Geomagnetic Pulsations Associated with the March 24, 1991 Geomagnetic Storm

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