Analysis of equatorial plasma bubble zonal drift velocities in the Pacific sector by imaging techniques

Yao, D.; Makela, J. J.

doi:10.5194/angeo-25-701-2007

Cited by 38 publications

(46 citation statements)

References 26 publications

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“…Using measurements of total electron content (TEC) and scintillations by Global Positioning System (GPS), the global longitudinal and seasonal occurrence of EPB and its vertical drifts in F region has been investigated by many researchers (Dashora et al, 2012;DasGupta et al, 1981;Li et al, 2008Li et al, , 2012. It is also well appreciated that the there is variation in zonal plasma drift day-to-day (Mukherjee and Shetti, 2008), seasonally (Yao and Makela, 2007) and with solar activity (Sahai et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Zonal velocity of the equatorial plasma bubbles over Kolhapur, India

et al. 2013

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Section: Introductionmentioning

confidence: 99%

Zonal velocity of the equatorial plasma bubbles over Kolhapur, India

et al. 2013

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“…They drift predominantly eastward with velocities of more than 100 m s −1 and are often tilted westward (see e.g. Sobral et al, 1999;Pimenta et al, 2003;Lin et al, 2005;Park et al, 2007;Yao and Makela, 2007;Makela and Kelley, 2003). Many climatological features of the ESF occurrence rates at specific locations in different longitude sectors have been revealed from the analyses of ground-based observations (see for example Fejer et al, 1999;Abdu et al, 2000;Sahai et al, 2004;Wiens et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Relation between the occurrence rate of ESF and the equatorial vertical plasma drift velocity at sunset derived from global observations

2008

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Abstract. In this study, we investigate two global climatological data sets; the occurrence rate of Equatorial Spread-F (ESF), associated with equatorial plasma irregularities, at ∼400 km altitude obtained from CHAMP observations, and the evening equatorial vertical plasma drift, v z , from ROCSAT-1 measurements. First, as retrieved for a solar flux level of F10.7=150, the longitudinal variation of the two independently derived quantities correlates between 84% and 93% in the seasons December solstice, equinox and June solstice. The highest correlation is found for the solstice seasons when v z is integrated over local time around the prereversal enhancement (PRE) and displaced 6 • towards east. The integrated v z is a suitable estimate of the ionospheric height at the time just after the PRE and the 6 • displacement is consistent with ESF eastward drift during 2 h which is assumed between creation and detection at satellite altitudes. Second, our analyses reveal a global threshold v z which is required to observe ESF at satellite altitudes. This threshold depends linearly on solar flux with correlations of 97%. Both results bring global evidence on the linear relations between ESF and the vertical plasma drift which have been proven only by local observations so far. This paper includes the first global map of the seasonal/longitudinal variation of the ESF occurrence rate over local time being valid for high solar flux years [2001][2002][2003][2004]. The map reveals, e.g. a longitudinal dependence of the persistence of the plasma irregularities indicating that longitude dependent mechanisms other than the PRE determine the ESF lifetime.

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“…Chandra et al, 1997;Sekar et al, 1997;Sinha et al, 1999), all-sky airglow camera (e.g. Mendillo and Tyler, 1983;Kim et al, 2002;Sahai et al, 2006;Yao and Makela, 2007), and space-based ultraviolet imager (e.g. Kelley et al, 2003;Immel et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

The characteristics of field-aligned currents associated with equatorial plasma bubbles as observed by the CHAMP satellite

et al. 2009

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Abstract. Field-aligned currents (FACs) generate magnetic deflections perpendicular to the ambient Earth magnetic field. We investigate the characteristics of FACs associated with equatorial plasma bubbles (EPBs) as deduced from magnetic field measurements by the CHAMP satellite. Meridional magnetic deflections inside EPBs show a clear hemispheric anti-symmetry for events observed before 21:00 LT: inward in the Northern Hemisphere and outward in the Southern Hemisphere. When an eastward electric field is assumed the magnetic signature signifies a Poynting flux directed downward along the magnetic field lines. This means that FACs are driven by a high-altitude equatorial source. Such a scheme cannot be drawn as strictly from our observations after 22:00 LT, possibly because of a westward turning of the electric field inside EPBs and/or a decay of EPBs later at night. The perpendicular magnetic deflection is tilted by 40 • from the magnetic meridional plane in westward direction, which implies that the depleted volume of EPBs, as well as the FAC structure, is tilted westward by 40 • above the magnetic equator. The peak-to-peak amplitude of the FAC density is found to range typically between 0.1-0.5 µA/m 2 . The field-aligned sheet current density and the diamagnetic current strength show no correlation.

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Analysis of equatorial plasma bubble zonal drift velocities in the Pacific sector by imaging techniques

Cited by 38 publications

References 26 publications

Zonal velocity of the equatorial plasma bubbles over Kolhapur, India

Zonal velocity of the equatorial plasma bubbles over Kolhapur, India

Relation between the occurrence rate of ESF and the equatorial vertical plasma drift velocity at sunset derived from global observations

The characteristics of field-aligned currents associated with equatorial plasma bubbles as observed by the CHAMP satellite

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