Multipoint spacecraft observations of long-lasting poloidal Pc4 pulsations in the dayside magnetosphere on 1–2 May 2014

Korotova, G. I.; Sibeck, D. G.; Engebretson, M. J.; Wygant, J. R.; Thaller, S. A.; Kletzing, C.; Angelopoulos, V.; Redmon, R. J.

doi:10.5194/angeo-34-985-2016

Cited by 15 publications

(17 citation statements)

References 42 publications

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“…One category of poloidal ULF waves is characterized by their long lifetime from several hours to days (e.g., Korotova et al, ; Le et al, ; Sarris et al, ). Most previous studies on the long‐lasting poloidal ULF waves were focused on wave properties in the magnetosphere (Korotova et al, ; Le et al, ; Min et al, ; Takahashi et al, ). Interestingly, the waves were usually monochromatic and observed during low geomagnetic activity after a geomagnetic storm or within the storm recovery phase, as summarized in Table .…”

Section: Introductionmentioning

confidence: 99%

Long‐Lasting Poloidal ULF Waves Observed by Multiple Satellites and High‐Latitude SuperDARN Radars

et al. 2018

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Poloidal ultralow frequency (ULF) waves between 5 and 10 mHz were observed by multiple satellites and three high-latitude Super Dual Auroral Radar Network radars during the recovery phase of a moderate geomagnetic storm on 24-27 January 2016. The long-lasting ULF waves were observed in the magnetic field and energetic particle flux perturbations during three successive passes by two Geostationary Operational Environmental Satellites through the dayside magnetosphere, during which plasmasphere expansion and refilling were observed by two Time History of Events and Macroscale Interactions during Substorms probes. The radial magnetic field oscillation was in phase (∼180 ∘ out of phase) with the northward (southward) moving proton flux oscillation at 95 keV, consistent with high-energy drift-bounce resonance signatures of protons with second harmonic poloidal standing Alfvén waves. The longitudinal extent of the waves approached 10 hr in local time on the dayside and gradually decreased with time. High-time-resolution (∼6 s) data from three high-latitude Super Dual Auroral Radar Network radars show that the wave intensification region was localized in latitude with a radial extent of ∼135-225 km in the subauroral ionosphere. No signature of these waves were observed by ground-based magnetometers colocated with the Geostationary Operational Environmental Satellites suggesting that the poloidal waves were high-m mode and thus screened by the ionosphere. During this interval one of the Time History of Events and Macroscale Interactions during Substorms probes observed a bump-on-tail ion distribution at 1-3 keV, which we suggest is the source of the long-lasting second harmonic poloidal ULF waves.

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Section: Introductionmentioning

confidence: 99%

Long‐Lasting Poloidal ULF Waves Observed by Multiple Satellites and High‐Latitude SuperDARN Radars

et al. 2018

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“…There have been numerous studies discussing excitation of poloidal waves by the drift‐bounce resonance (e.g., Anderson et al, ; Engebretson et al, ; Hughes et al, ; Kokubun et al, ; Korotova et al, ; Liu et al, ; Min et al, ; Takahashi et al, ). Large‐m poloidal waves are thought to be excited by the drift‐bounce resonance mechanism associated with hot ring current protons (Anderson et al, ; Kokubun et al, ).…”

Section: Introductionmentioning

confidence: 99%

Van Allen Probes Observations of Drift‐Bounce Resonance and Energy Transfer Between Energetic Ring Current Protons and Poloidal Pc4 Wave

et al. 2018

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A poloidal Pc4 wave and proton flux oscillations are observed in the inner magnetosphere on the dayside near the magnetic equator by the Van Allen Probes spacecraft on 2 March 2014. The flux oscillations are observed in the energy range of 67.0 to 268.8 keV with the same frequency of the poloidal Pc4 wave. We find pitch angle and energy dispersion in the phase difference between the poloidal magnetic field and the proton flux oscillations, which are features of drift-bounce resonance. We estimate the resonance energy to be~120 keV for pitch angle (α) of 30°or 150°and 170-180 keV for α = 50°or 130°. To examine the direction of energy flow between protons and the wave, we calculate the sign of the gradient of proton phase space density (df/dW) on both the inbound and outbound legs of the orbit. We find the gradient to be outward on both legs, which means that energy is transferred from the protons to the wave. During the poloidal Pc4 wave event, the Dst* index shows a measurable increase of~6.7 nT. We estimate the total energy loss of the ring current from the recovery of the Dst* index and from the variation of proton flux by the drift-bounce resonance. We suggest that energy transfer from the ring current protons to the poloidal Pc4 wave via the drift-bounce resonance contributes to up to~85% of the increase of the Dst* index.Poloidal ULF waves are capable of resonating with charged particles through their azimuthal wave electric fields. This wave-particle interaction is known as drift-bounce resonance. Drift-bounce resonant condition is expressed aswhere ω is the wave angular frequency, ω d is the particle drift frequency, ω b is the particle bounce frequency, and N is an integer (Southwood et al., 1969). The drift-bounce resonance condition can be satisfied with odd mode ULF waves when N = 2k (k is an integer), while it can be satisfied with even mode ULF waves when OIMATSU ET AL. 3421

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“…Zong et al [2009] studied shock-excited waves using nine satellites and observed both poloidal and toroidal waves with comparable intensity at L = 4.4, but only toroidal waves at geosynchronous orbit. Korotova et al [2016] observed poloidal waves that occurred simultaneously over a local time extent of~10 h during the recovering phase of a magnetic storm. In this paper, we report a rare example in which storm time high-m poloidal waves are observed globally by 15 satellites from five missions including Magnetospheric Multiscale (MMS), Van Allen Probes, Time History of Events and Macroscale Interactions during Substorm (THEMIS), Cluster, and Geostationary Operational Environmental Satellites (GOES), covering L values between~4 and 12 as well as local times from the morning, noon, afternoon, and postdusk local time sectors.…”

Section: Introductionmentioning

confidence: 99%

Global observations of magnetospheric high‐m poloidal waves during the 22 June 2015 magnetic storm

Strangeway

et al. 2017

Geophysical Research Letters

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We report global observations of high‐m poloidal waves during the recovery phase of the 22 June 2015 magnetic storm from a constellation of widely spaced satellites of five missions including Magnetospheric Multiscale (MMS), Van Allen Probes, Time History of Events and Macroscale Interactions during Substorm (THEMIS), Cluster, and Geostationary Operational Environmental Satellites (GOES). The combined observations demonstrate the global spatial extent of storm time poloidal waves. MMS observations confirm high azimuthal wave numbers (m ~ 100). Mode identification indicates the waves are associated with the second harmonic of field line resonances. The wave frequencies exhibit a decreasing trend as L increases, distinguishing them from the single‐frequency global poloidal modes normally observed during quiet times. Detailed examination of the instantaneous frequency reveals discrete spatial structures with step‐like frequency changes along L. Each discrete L shell has a steady wave frequency and spans about 1 RE, suggesting that there exist a discrete number of drift‐bounce resonance regions across L shells during storm times.

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Multipoint spacecraft observations of long-lasting poloidal Pc4 pulsations in the dayside magnetosphere on 1–2 May 2014

Cited by 15 publications

References 42 publications

Long‐Lasting Poloidal ULF Waves Observed by Multiple Satellites and High‐Latitude SuperDARN Radars

Long‐Lasting Poloidal ULF Waves Observed by Multiple Satellites and High‐Latitude SuperDARN Radars

Van Allen Probes Observations of Drift‐Bounce Resonance and Energy Transfer Between Energetic Ring Current Protons and Poloidal Pc4 Wave

Global observations of magnetospheric high‐m poloidal waves during the 22 June 2015 magnetic storm

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