Global observations of the zonal drift speed of equatorial ionospheric plasma bubbles

Immel, T. J.; Frey, H. U.; Mende, S. B.; Sagawa, E.

doi:10.5194/angeo-22-3099-2004

Cited by 42 publications

(51 citation statements)

References 41 publications

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“…The results presented above reveal a significant day-to-day variability in magnitudes of the plasma drift zonal velocities, however, the trends of the variations with the local time is similar. The plots as explained above (Figure 2-4), show that daytime plasma drifts are westward, while the night-time drifts are eastward, which is consistent with the previous results [3,4,12,15]. Similarly, increase in the plasma drifts has been seen shortly after sunset (see in Figures 2-4) as the drift reverses from westward to eastward from the day to night transition.…”

Section: Resultssupporting

confidence: 79%

Equatorial ionospheric plasma drifts velocities using radar observations

Chapagain

2016

BIBECHANA

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This study presents the experimental results of the equatorial ionospheric plasma drift zonal velocity obtained from Incoherent Scatter Radar (ISR) observations for 6 selective days in 2011 from Jicamarca, Peru. Our results indicate that the daytime drifts are westward with peak values mostly below ~50 m/s, while the night time drifts velocities are eastward, with a maximum value up to 120 m/s at around local midnight hours. The drift velocity decreases during post-midnight hours and starts to reverse westward in early morning hours. Our plasma drifts results are in good agreement with results from previous radar studies and other measurement techniques.

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Section: Resultssupporting

confidence: 79%

Equatorial ionospheric plasma drifts velocities using radar observations

Chapagain

2016

BIBECHANA

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“…They existed within the wide band-like airglow regions that correspond with the equatorial anomalies in both hemispheres. New bright airglow patches were successively created with time near the solar terminator, resulting in an apparent motion of the airglow patches to the west: actually the alternately bright and faint airglow regions moved to the east together, as has been demonstrated by Sagawa et al (2003) and Immel et al (2003Immel et al ( , 2004. The FOVs (1000 km in diameter) of the Shigaraki and Darwin all-sky imagers are indicated in Fig.…”

Section: Image Observationsmentioning

confidence: 99%

“…This camera was designed to take auroral pictures, but as demonstrated by Sagawa et al (2003) and Immel et al (2003Immel et al ( , 2004, the instrument is also sensitive enough to image the low-latitude ionosphere at night. The camera on the satellite located at 7 Re altitude can take an image with a spatial resolution of 90 km × 90 km at ionospheric altitudes and a temporal resolution of 2 min (satellite spin period).…”

Section: Observations and Analysismentioning

confidence: 99%

“…In particular, Sagawa et al (2003) have first used an OI 135.6-nm imager onboard the IMAGE satellite, which reaches an apogee of nearly 7 earth radii (Re), to find 1000 km-scale wavy plasma structures embedded in the northern and southern equatorial anomaly regions. Then, using a large number of IMAGE images, Immel et al (2003Immel et al ( , 2004 have clarified some characteristics of drift velocity of these plasma structures. Kelley et al (2003) have reported coordinated observations of plasma bubbles from space (OI 135.6-nm imager on the TIMED satellite in a near circular orbit at 630-km altitude) and the ground (OI 777.4-nm imager in Hawaii).…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous ground- and satellite-based airglow observations of geomagnetic conjugate plasma bubbles in the equatorial anomaly

et al. 2005

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We compare, for the first time, geomagnetically-conjugate plasma bubbles observed by ground-based OI 630.0-nm all-sky imagers at Shigaraki, Japan (34.8• N, 136.1 • E; magnetic latitude 25.4• N) and Darwin, Australia (12.4• S, 131.0 • E; magnetic latitude 22.0 • S), with global-scale plasma structures (∼10,000 km in longitude) in the equatorial anomaly simultaneously detected with an OI 135.6-nm imager on the IMAGE satellite at ∼7 earth radii. As found previously, global-scale plasma structures in both hemisphere imaged by IMAGE consist of an array of geomagnetically-conjugate small-to medium-scale (a few hundreds to 1000 km in longitude) wavy structures that move to the east at ∼100 m s −1 . We find the following: 1) plasma bubbles detected with the allsky imagers reach an apex altitude of ∼1800 km over the geomagnetic equator while moving to the east at ∼100 m s −1 with spacings of 200-250 km. 2) Bubbles observed with the all-sky imagers and IMAGE are embedded within the small-to medium-scale wavy structures, and some of them are located near the crest of an enhanced electron density region associated with the wavy structures.3) The bubbles and wavy structures that are generated near sunset slant to the west with increasing latitude in both hemispheres, and tilts do not change with longitude (i.e., local time). The results suggest that the generation and evolution of plasma bubbles are closely related to those of the small-to medium-scale plasma structures.

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“…Space-based far ultraviolet (FUV) optical measurements from an imager aboard the IMAGE satellite revealed that the zonal drift velocity of equatorial plasma bubbles largely depends on the longitude (Immel et al, 2004). The highest velocity was 9.9 • /h (306 m/s) around the Indian sector, while the mean speed was 6.5 • /h (200 m/s).…”

Section: Drift Velocity and Spatial Structurementioning

confidence: 99%

Equatorial ionospheric disturbance observed through a transequatorial HF propagation experiment

Maruyama

Kawamura

2006

Ann. Geophys.

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Abstract.A transequatorial radio-wave propagation experiment at shortwave frequencies (HF-TEP) was done between Shepparton, Australia, and Oarai, Japan, using the radio broadcasting signals of Radio Australia. The receiving facility at Oarai was capable of direction finding based on the MUSIC (Multiple Signal Classification) algorithm. The results were plotted in azimuth-time diagrams (AT plots). During the daytime, the propagation path was close to the great circle connecting Shepparton and Oarai, thus forming a single line in the AT plots. After sunset, off-great-circle paths, or satellite traces in the AT plot, often appeared abruptly to the west and gradually returned to the great circle direction. However, there were very few signals across the great circle to the east. The off-great-circle propagation was very similar to that previously reported and was attributed to reflection by an ionospheric structure near the equator. From the rate of change in the direction, we estimated the drift velocity of the structure to range mostly from 100 to 300 m/s eastward. Multiple instances of off-great-circle propagation with a quasi-periodicity were often observed and their spatial distance in the east-west direction was within the range of large-scale traveling ionospheric disturbances (LS-TIDs). Off-great-circle propagation events were frequently observed in the equinox seasons. Because there were many morphological similarities, the events were attributed to the onset of equatorial plasma bubbles.

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Global observations of the zonal drift speed of equatorial ionospheric plasma bubbles

Cited by 42 publications

References 41 publications

Equatorial ionospheric plasma drifts velocities using radar observations

Equatorial ionospheric plasma drifts velocities using radar observations

Simultaneous ground- and satellite-based airglow observations of geomagnetic conjugate plasma bubbles in the equatorial anomaly

Equatorial ionospheric disturbance observed through a transequatorial HF propagation experiment

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