Giant pulsations as modes of a transverse Alfvénic resonator on the plasmapause

Mager, P. N.; Klimushkin, D. Yu.

doi:10.5047/eps.2012.10.002

Cited by 25 publications

(32 citation statements)

References 66 publications

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“…The trough in the Alfvén speed profile forms a resonance in the similar way of forming the ionospheric Alfvén resonator at several thousand kilometers above Earth [ Lysak , ]. Mode trapping near the plasmapause has been theoretically considered [ Klimushkin , ; Lee and Kim , ; Leonovich and Mazur , ; Klimushkin et al , ; Mager and Klimushkin , ]. Takahashi et al [, ] provide observation evidence of compressional Pc4 waves trapped by the plasmapause on the dayside.…”

Section: Introductionmentioning

confidence: 99%

Storm time occurrence and spatial distribution of Pc4 poloidal ULF waves in the inner magnetosphere: A Van Allen Probes statistical study

et al. 2015

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Poloidal ULF waves are capable of efficiently interacting with energetic particles in the ring current and the radiation belt. Using Van Allen Probes (Radiation Belt Storm Probes (RBSP)) data from October 2012 to July 2014, we investigate the spatial distribution and storm time occurrence of Pc4 (7–25 mHz) poloidal waves in the inner magnetosphere. Pc4 poloidal waves are sorted into two categories: waves with and without significant magnetic compressional components. Two types of poloidal waves have comparable occurrence rates, both of which are much higher during geomagnetic storms. The noncompressional poloidal waves mostly occur in the late recovery phase associated with an increase of Dst toward 0, suggesting that the decay of the ring current provides their free energy source. The occurrence of dayside compressional Pc4 poloidal waves is found correlated with the variation of the solar wind dynamic pressure, indicating their origin in the solar wind. Both compressional and noncompressional waves preferentially occur on the dayside near noon at L∼5–6. In addition, compressional poloidal waves are observed at magnetic local time 18–24 on the nightside. The location of the Pc4 poloidal waves relative to the plasmapause is investigated. The RBSP statistical results may shed light on the in‐depth investigations of the generation and propagation of Pc4 poloidal waves.

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Section: Introductionmentioning

confidence: 99%

Storm time occurrence and spatial distribution of Pc4 poloidal ULF waves in the inner magnetosphere: A Van Allen Probes statistical study

et al. 2015

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“…During the main phase of an intense geomagnetic storm, Pilipenko et al [, ] was able to use ground magnetometers to identify high‐ m waves among Pi3 pulsations, where Pi3 waves can be the ground counterparts of Pc5 pulsations observed using satellites, as was found in Vaivads et al [] for Ps6 waves, a variety of Pi3 wave. It is possible for large amplitude waves with moderately large azimuthal wave numbers, (| m |=15–40), such as giant pulsations, Pg [e.g., Chisham , ; Chisham et al , ; Mager and Klimushkin , ], to overcome the screening of the ionosphere in order to be observed by ground magnetometers. The westward phase velocity of ground Pg, Pi3, and Ps6 pulsations, like the majority of poloidal pulsations observed by spacecraft is consistent with the idea that the energy source of high‐ m waves is within populations of westward drifting energetic protons.…”

Section: Introductionmentioning

confidence: 99%

Multiradar observations of substorm‐driven ULF waves

et al. 2016

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A recent statistical study of ULF waves driven by substorm‐injected particles observed using Super Dual Auroral Radar Network (SuperDARN) found that the phase characteristics of these waves varied depending on where the wave was observed relative to the substorm. Typically, positive azimuthal wave numbers, m, were observed in waves generated to the east of the substorms and negative m to the west. The magnitude of m typically increased with the azimuthal separation between the wave observation and the substorm location. The energies estimated for the driving particles for these 83 wave events were found to be highest when the waves were observed closer to the substorm and lowest farther away. Each of the 83 events studied by James et al. (2013) involved just a single wave observation per substorm. Here a study of three individual substorm events are presented, with associated observations of multiple ULF waves using various different SuperDARN radars. We demonstrate that a single substorm is capable of driving a number of wave events characterized by different azimuthal scale lengths and wave periods, associated with different energies, W, in the driving particle population. We find that similar trends in m and W exist for multiple wave events with a single substorm as was seen in the single wave events of James et al. (2013). The variety of wave periods present on similar L shells in this study may also be evidence for the detection of both poloidal Alfvén and drift compressional mode waves driven by substorm‐injected particles.

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“…By studying a few wave events with the Active Magnetospheric Particle Tracer Explorers/Ion Release Module data, Denton et al [] found observational support to this global poloidal mode theory and considered that the dip in poloidal frequency might result from the L dependence of the equilibrium density or magnetic field. More recently, this region where wave energy can be trapped is also called the “transverse Alfvénic resonator,” which can exist not only in the ring current region but also near the plasmpause as well [ Mager and Klimushkin , ; Yeoman et al , ].…”

Section: Introductionmentioning

confidence: 99%

“…The most promising theory to explain such a feature is proposed by Chen [1994, 1996], who show that an energetically trapped global poloidal mode can exist in a region in which the poloidal Alfvén frequency is lower than the toroidal frequency and where it exhibits a dip (minimum) with respect to L. By studying a few wave events with the Active Magnetospheric Particle Tracer Explorers/Ion Release Module data, Denton et al [2003] found observational support to this global poloidal mode theory and considered that the dip in poloidal frequency might result from the L dependence of the equilibrium density or magnetic field. More recently, this region where wave energy can be trapped is also called the "transverse Alfvénic resonator," which can exist not only in the ring current region but also near the plasmpause as well [Mager and Klimushkin, 2013;Yeoman et al, 2012].…”

Section: Introductionmentioning

confidence: 99%

Observations of magnetospheric high‐m poloidal waves by ST‐5 satellites in low Earth orbit during geomagnetically quiet times

2015

JGR Space Physics

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The poloidal waves with large azimuthal wave numbers (m) in the magnetosphere are known to be generated by drift or drift‐bounce resonance with energetic ring current particles, and these waves may play a role in modulating the energetic particles in the inner magnetosphere. When examining the magnetic field data collected by the NASA Space Technology 5 (ST‐5) satellites in the low Earth orbit, Le et al. (2011) discovered many wave events with frequencies of 30–200 mHz (in the Pc2 and Pc3 bands), and they proposed that these waves should, in fact, be Doppler‐shifted high‐m poloidal waves in the magnetosphere with frequencies at only a few millihertz (in the Pc5 band). Using a new method that examines the differences in wave phase detected by the three ST‐5 satellites, we confirm that the frequencies in the Earth frame for the poloidal waves observed are mainly between 3 and 5 mHz. Not only were poloidal waves observed frequently by ST‐5 in the dayside magnetosphere but they were also occasionally seen in the nightside when the satellites passed through the same L shells. In each wave event, the azimuthal wave number may change with L, but the wave frequency in the Earth frame remains the same. We also find that poloidal waves can last more than 9 h during geomagnetically quiet conditions, suggesting that even a very weak ring current can supply enough energetic particles to excite poloidal waves.

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Giant pulsations as modes of a transverse Alfvénic resonator on the plasmapause

Cited by 25 publications

References 66 publications

Storm time occurrence and spatial distribution of Pc4 poloidal ULF waves in the inner magnetosphere: A Van Allen Probes statistical study

Storm time occurrence and spatial distribution of Pc4 poloidal ULF waves in the inner magnetosphere: A Van Allen Probes statistical study

Multiradar observations of substorm‐driven ULF waves

Observations of magnetospheric high‐m poloidal waves by ST‐5 satellites in low Earth orbit during geomagnetically quiet times

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