Pi2 pulsation simultaneously observed in the <i>E</i> and <i>F</i> region ionosphere with the SuperDARN Hokkaido radar

Teramoto, Masaaki; Нишитани, Н.; Pilipenko, Vyacheslav; Ogawa, T.; Shiokawa, K.; Nagatsuma, Tsutomu; Yoshikawa, Akimasa; Baishev, D. G.; Murata, Ken T.

doi:10.1002/2012ja018585

Cited by 10 publications

(9 citation statements)

References 44 publications

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“…These observations supported the Direct Response Bursty Bulk Flow model (DR‐BBF), in which ground instruments directly sense compressional waves generated by BBF braking [ Kepko and Kivelson , ]. By contrast, Teramoto et al [] compared SuperDARN Hokkaido radar Pi2 observations with theoretical predictions and suggested that a cavity mode together with the contribution of an Alfvén wave can account for some midlatitude Pi2s. More recently, Teramoto et al [] used multipoint observations from three midlatitude SuperDARN radars, three Time History of Events and Macroscale Interactions During Substorms (THEMIS) satellites, and ground magnetometers to study the latitudinal dependence of Pi2 frequency near the plasmapause.…”

Section: Introductionmentioning

confidence: 70%

“…However, except for the compressional wave components ( E y and B z ), the other electric field and magnetic field components ( E x , B x , and B y ) from THD oscillated with much smaller amplitudes, as can be seen in Figure . Therefore, a mixture of other wave modes, such as propagating fast waves and/or shear Alfvén waves, together with a predominant standing fast wave, is a plausible scenario [ Teramoto et al , ; Lysak et al , ].…”

Section: Observations and Analysismentioning

confidence: 99%

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Simultaneous space and ground‐based observations of a plasmaspheric virtual resonance

et al. 2017

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We present simultaneous space and ground‐based observations of Pi2 pulsations which occurred during a substorm on 25 September 2014. The timeline for this event starts at ∼06:04 UT when the THEMIS probe D located inside the plasmasphere detected Pi2 pulsations in the electric and magnetic fields. Cross‐spectral analysis shows the azimuthal electric field and compressional magnetic field oscillated nearly in quadrature, highly suggestive of a standing fast‐mode wave. Simultaneous Pi2 observations from dayside and nightside ground magnetometers at low latitudes indicate a global wave mode. A latitudinal magnetometer chain on the nightside observed a phase reversal in the H component of the Pi2 pulsations when crossing the footprint of the plasmapause, estimated from THEMIS spacecraft measurements. Spectral analysis of data from ground magnetometers in this latitudinal chain showed fundamental and second harmonic spectral peaks in their H and D components. Similar pulsation signatures at comparable harmonic frequencies were observed by three midlatitude SuperDARN HF radars, both poleward and equatorward of the plasmapause ionospheric footprint. Finally, the longitudinal polarization pattern and azimuthal phase propagation of midlatitude Pi2 pulsations are consistent with previous observations of a plasmaspheric virtual resonance being excited by a longitudinally localized source near midnight.

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Section: Introductionmentioning

confidence: 70%

Section: Observations and Analysismentioning

confidence: 99%

Simultaneous space and ground‐based observations of a plasmaspheric virtual resonance

et al. 2017

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“…Although radar observations are capable of investigating the spatial structure of Pi2 pulsations at mid latitudes (36°-60°), only a few studies have investigated Pi2 pulsations by using the SuperDARN radars at mid latitudes (Ponomarenko et al 2003;Gjerloev et al 2007;Frissell et al 2011;Teramoto et al 2014). To investigate generation mechanisms of Pi2 pulsations, multipoint observations are needed because Pi2 pulsations are globally excited in the mid and low latitudes.…”

Section: Introductionmentioning

confidence: 99%

Latitudinal dependence on the frequency of Pi2 pulsations near the plasmapause using THEMIS satellites and Asian-Oceanian SuperDARN radars

et al. 2016

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We herein describe a harmonic Pi2 wave that started at 09:12 UT on August 19, 2010, with data that were obtained simultaneously at 19:00-20:00 MLT by three mid-latitude Asian-Oceanian Super Dual Auroral Radar Network (SuperDARN) radars (Unwin, Tiger, and Hokkaido radars), three Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites (THEMIS A, THEMIS D, and THEMIS E), and ground-based magnetometers at low and high latitudes. All THEMIS satellites, which were located in the plasmasphere, observed Pi2 pulsations dominantly in the magnetic compressional (B // ) and electric azimuthal (E A ) components, i.e., the fast-mode component. The spectrum of Pi2 pulsations in the B // and E A components contained two spectral peaks at approximately 12 to 14 mHz (f 1 , fundamental) and 23 to 25 mHz (f 2 , second harmonic). The Poynting flux derived from the electric and magnetic fields indicated that these pulsations were waves propagating earthward and duskward. Doppler variations (V) from the 6-s or 8-s resolution camping beams of the Tiger and Unwin SuperDARN radars, which are associated with Pi2 pulsations in the eastward electric field component in the ionosphere, observed Pi2 pulsations within and near the footprint of the plasmapause, whose location was estimated by the THEMIS satellites. The latitudinal profile of f 2 power normalized by f 1 power for Doppler velocities indicated that the enhancement of the normalized f 2 power was the largest near the plasmapause at an altitude-adjusted corrected geomagnetic (AACGM) latitude of 60°to 65°. Based on these features, we suggest that compressional waves propagate duskward away from the midnight sector, where the harmonic cavity mode is generated.

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“…The global nature of Pi2 wave propagation presents challenges for modeling these pulsations. Pi2 pulsations are observed by spacecraft in a variety of orbits [e.g., Takahashi et al ., , ; Sutcliffe and Lühr , , ; Luo et al ., ], by ground magnetometers [e.g., Saito et al ., ; Samson , ; Yumoto , ; Shinohara et al ., ], and by radars that measure ionospheric flows [e.g., Ponomarenko et al ., ; Gjerloev et al ., ; Teramoto et al ., ]. Global MHD models are limited in describing higher frequency pulsations.…”

Section: Introductionmentioning

confidence: 99%

Propagation of Pi2 pulsations in a dipole model of the magnetosphere

et al. 2015

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Localized fast flows that impinge on the inner magnetosphere from the plasma sheet are observed to oscillate on time scales of minutes. The compression ahead of these flows will launch fast mode waves, while the velocity shears at the edges of these flows directly excite shear Alfvén waves. These waves, which are coupled by gradients in the Alfvén speed, have been suggested as a source for the Pi1 and Pi2 waves that are observed at both high and low latitudes in the ionosphere. A new three-dimensional simulation of the propagation of ULF waves in the dipolar region of the magnetosphere has been developed to study these coupled wave modes. This model includes a height-resolved ionospheric conductivity so that ionospheric fields can be more realistically determined, as well as a direct calculation of ground magnetic fields to compare with ground magnetometers using an inductive ionosphere model. Results from this model show that a plasmaspheric resonance can be set up by waves with periods about 1 min and that field line resonances can be excited both inside and outside the plasmasphere. The use of the inductive ionosphere model leads to the conclusion that even a uniform Hall conductivity can break the dawn-dusk symmetry of the convection pattern. Waves from a source at 10 Earth radii reach the ionosphere with time delays between high and low latitudes of tens of seconds, with implications for the timing of substorm phenomena observed by spacecraft and by ground magnetometers and radars.

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Pi2 pulsation simultaneously observed in the E and F region ionosphere with the SuperDARN Hokkaido radar

Cited by 10 publications

References 44 publications

Simultaneous space and ground‐based observations of a plasmaspheric virtual resonance

Simultaneous space and ground‐based observations of a plasmaspheric virtual resonance

Latitudinal dependence on the frequency of Pi2 pulsations near the plasmapause using THEMIS satellites and Asian-Oceanian SuperDARN radars

Propagation of Pi2 pulsations in a dipole model of the magnetosphere

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