Perkins instability revisited

Hamza, A. M.

doi:10.1029/1999ja900307

Cited by 49 publications

(51 citation statements)

References 6 publications

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“…The low elevation viewing geometry of CNFI and PICASSO could inhibit the detection of MSTIDs, as the look directions of these instruments integrate through MSTID wavefronts. Another plausible explanation for the occurrence difference is due to the growth rate of MSTIDs being proportional to sin 2 D, where D is the magnetic inclination angle (Perkins, 1973;Hamza, 1999). The fields of view of CNFI and PICASSO encompass smaller inclination angles, thus the growth rate, and consequently the occurrence rate is smaller at these locations.…”

Section: Annmentioning

confidence: 99%

Climatology of nighttime medium-scale traveling ionospheric disturbances (MSTIDs) in the Central Pacific and South American sectors

2013

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Abstract. We present occurrence rate statistics for nighttime medium-scale traveling ionospheric disturbances (MSTIDs) in the Central Pacific and South American sectors using data collected by 630.0 nm filtered CCD imaging systems. The data were collected from September 2006 through December 2012. In general, the statistics are in good agreement with the basic linear theory of MSTIDs, with observations coinciding with low F10.7A values, representative of solar minimum. Overall, MSTIDs are observed in approximately 68 % of the usable nights near the solstices at mid-latitudes and approximately 20 % of the usable nights for equinox periods. Observations closer to the geomagnetic equator yielded a maximum occurrence rate of about 10-20 % during the solstices and about 0-3 % during the equinoxes. The lower number of MSTID observations near the low latitudes is attributed to limitations of MSTID growth rate, propagation, and/or geometrical observational effects. The relatively large number of MSTID occurrences during the solstices can be accounted for by the neutral wind contribution to the MSTID growth rate either at the local or magnetic conjugate point.

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Section: Annmentioning

confidence: 99%

Climatology of nighttime medium-scale traveling ionospheric disturbances (MSTIDs) in the Central Pacific and South American sectors

2013

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“…Perkins (1973) presented a model that was used to explain the mid-latitude structures. Later, Hamza (1999) Figure. 1.…”

Section: Introductionmentioning

confidence: 99%

Observations of GPS ionospheric scintillations over Wuhan during geomagnetic storms

Ning

Wan

2006

Ann. Geophys.

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Abstract. During the two geomagnetic storms which occurred on 1 October 2002 and 22 January 2004, the strong ionospheric scintillations of the GPS L1 band were observed at Wuhan station (30.6 • N, 114.4 • E, 45.8 • Dip), which is situated near the northern crest of the equatorial ionosphere anomaly. We found that the intense scintillations were associated with the main phases of the storms and were colocated with the enhancement of the equatorial ionization anomaly (EIA); the co-existence of large-and small-scale irregularities at post-midnight was also found. The results may be relevant regarding the influence of the equatorial ionospheric eastward electric field during geomagnetic storms. On the other hand, GPS L1 band scintillations were not observed during the other two similar storms on 16 July 2003 and 20 November 2003. One of the reasons is probably that the sporadic E layer observed at the storms inhibited the generation of spread F by changing the Pedersen conductivity and suppressing the upward plasma drift.

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“…Traveling ionospheric disturbances (TIDs) are a manifestation of the interactions between the ionized atmosphere and atmospheric gravity waves (Hines, 1964;Hooke, 1968;Perkins, 1973;Francis, 1974;Hamza, 1999). The new technique of wide-angle airglow imaging gives the two-dimensional structure and direction of motion of the TIDs.…”

Section: Introductionmentioning

confidence: 99%

Imaging observations of the equatorward limit of midlatitude traveling ionospheric disturbances

et al. 2014

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This paper reports the first attempt to observe the equatorward limit of medium-scale traveling ionospheric disturbances (TIDs) in the middle latitudes. The TIDs usually propagate southwestward in the northern hemisphere. An all-sky cooled-CCD imager measured 630-nm airglow at a southern island of Japan, Okinawa (26.9 • N, 128.3• E, geomagnetic latitude (MLAT) = 17.0• ), during the FRONT-2 campaign of August 4-15, 1999. The TIDs were detected at the mainland of Japan (∼21• -36• MLAT) by the total electron content (TEC) observations of more than 1000 GPS receivers. In the August 4 event, the TIDs moving southwestward was seen only in the northern sky of Okinawa as a depletion band in the 630-nm airglow images. In the August 6 event, the TIDs were not seen in the 630-nm images at Okinawa, although weak TID activity was observed by the GPS network at the mainland of Japan. The TEC data also showed weakening of the TID activity below 18• MLAT. Based on these observations, we suggest that there is a possible limit of medium-scale TID propagation around ∼18• MLAT.

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Perkins instability revisited

Cited by 49 publications

References 6 publications

Climatology of nighttime medium-scale traveling ionospheric disturbances (MSTIDs) in the Central Pacific and South American sectors

Climatology of nighttime medium-scale traveling ionospheric disturbances (MSTIDs) in the Central Pacific and South American sectors

Observations of GPS ionospheric scintillations over Wuhan during geomagnetic storms

Imaging observations of the equatorward limit of midlatitude traveling ionospheric disturbances

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