scholarly journals ASSOCIATION BETWEEN IONOSPHERIC PLASMA BUBBLES AND SPREAD-F

2005 ◽  
Author(s):  
H. Castilho ◽  
Vivian Moreira ◽  
José Humberto Andrade; Abdu ◽  
Mangalathayil Ali; Arruda ◽  
Daniela Cristina
Keyword(s):  
Ionospheric Plasma ◽  
Plasma Bubbles ◽  
Spread F

scholarly journals Simultaneous observation of ionospheric plasma bubbles and mesospheric gravity waves during the SpreadFEx Campaign

2009 ◽  
Vol 27 (4) ◽  
pp. 1477-1487 ◽  
Author(s):  
H. Takahashi ◽  
M. J. Taylor ◽  
P.-D. Pautet ◽  
A. F. Medeiros ◽  
D. Gobbi ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Ionospheric Plasma ◽  
Bubble Formation ◽  
South American ◽  
Plasma Bubble ◽  
Simultaneous Observation ◽  
Plasma Bubbles ◽  
Spread F ◽  
The Relationship ◽  
Horizontal Wavelength

Abstract. During the Spread F Experiment campaign, under NASA Living with a Star (LWS) program, carried out in the South American Magnetic Equator region from 22 September to 8 November 2005, two airglow CCD imagers, located at Cariri (7.4° S, 36.5° W, geomag. 11° S) and near Brasilia (14.8° S, 47.6° W, geomag. 10° S) were operated simultaneously and measured the equatorial ionospheric bubbles and their time evolution by monitoring the airglow OI 6300 intensity depletions. Simultaneous observation of the mesospheric OH wave structures made it possible to investigate the relationship between the bubble formation in the ionosphere and the gravity wave activity at around 90 km. On the evening of 30 September 2005, comb-like OI 6300 depletions with a distance of ~130 km between the adjacent ones were observed. During the same period, a mesospheric gravity wave with a horizontal wavelength of ~130 km was observed. From the 17 nights of observation during the campaign period, there was a good correlation between the OI 6300 depletion distances and the gravity wave horizontal wavelengths in the mesosphere with a statistically significant level, suggesting a direct contribution of the mesospheric gravity wave to plasma bubble seeding in the equatorial ionosphere.

scholarly journals ASSOCIATION BETWEEN IONOSPHERIC PLASMA BUBBLES AND SPREAD-F

2005 ◽  
Author(s):  
Vivian Moreira Castilho ◽  
José Humberto Andrade Sobral ◽  
Mangalathayil Ali Abdu ◽  
Daniela Cristina Santana Arruda
Keyword(s):  
Ionospheric Plasma ◽  
Plasma Bubbles ◽  
Spread F

Ionospheric Plasma Bubbles Over South America: Scientific Studies And Evidences Of Their Interference In Telecommunications

2001 ◽  
Author(s):  
J.H.A. Sobral ◽  
M.A. Abdu ◽  
H. Takahashi ◽  
E.R. de Paula ◽  
I.S. Batista ◽  
...  
Keyword(s):  
South America ◽  
Ionospheric Plasma ◽  
Plasma Bubbles

CARACTERISTICS OF IONOSPHERIC PLASMA BUBBLES OBSERVED BY TEC MAPS IN BRAZILIAN SECTOR

2017 ◽  
Author(s):  
Diego Barros Silva ◽  
Hisao Takahashi ◽  
Cristiano Max Wrasse ◽  
Cosme Alexandre Oliveira Barros Figueireido
Keyword(s):  
Ionospheric Plasma ◽  
Plasma Bubbles

scholarly journals Semimonthly oscillation observed in the start time of equatorial Spread-F

2019 ◽  
Author(s):  
Igo Paulino ◽  
Ana Roberta Paulino ◽  
Ricardo Yvan de la Cruz Cueva ◽  
Ebenezer Agyei-Yeboah ◽  
Ricardo Arlen Buriti ◽  
...  
Keyword(s):  
Radar Data ◽  
Ionospheric Irregularities ◽  
Start Time ◽  
Bottom Type ◽  
Equatorial Spread F ◽  
Complete Cycle ◽  
Plasma Bubbles ◽  
Spread F ◽  
Using Data ◽  
Coherent Backscatter

Abstract. Using data from airglow an all sky imager and a coherent backscatter radar deployed at São João do Cariri (7.4° S, 36.5° W) and São Luís (2.6° S, 44.2° W), respectively, the start time of equatorial Spread-F were studied. Data from a period of over 10 years was investigated from 2000 to 2010. The semimonthly oscillations were clearly revealed in the start time of plasma bubbles from Oi6300 airglow images during three periods (September 2003, September–October 2005, November 2005 and January 2008). Since the airglow measurements are not continuous in time, more than one cycle of oscillation in the start time of plasma bubbles cannot be observed from these data. Thus, coherent backscatter radar data appeared as an alternative to investigate the start time of the ionospheric irregularities. Semimonthly oscillation were observed in the start time of plumes (November 2005) and bottom type Spread-F (November 2008) with at least one complete cycle. Technical/climate issues did not allowed to observe the semimonthly oscillations simultaneously by the two instruments, but from September to December 2005 there was a predominance of this spread-F start time oscillation over Brazil. The presence of this oscillation certainly contribute to the day-to-day variability of spread-F.

scholarly journals Simultaneous observations of equatorial F-region plasma depletions over Brazil during the Spread-F Experiment (SpreadFEx)

2009 ◽  
Vol 27 (6) ◽  
pp. 2371-2381 ◽  
Author(s):  
P.-D. Pautet ◽  
M. J. Taylor ◽  
N. P. Chapagain ◽  
H. Takahashi ◽  
A. F. Medeiros ◽  
...  
Keyword(s):  
Gravity Wave ◽  
State University ◽  
Large Area ◽  
Plasma Bubbles ◽  
F Region ◽  
Equatorial Plasma Bubbles ◽  
Star Program ◽  
Spread F ◽  
Plasma Depletions ◽  
Bubble Characteristics

Abstract. From September to November 2005, the NASA Living with a Star program supported the Spread-F Experiment campaign (SpreadFEx) in Brazil to study the effects of convectively generated gravity waves on the ionosphere and their role in seeding Rayleigh-Taylor instabilities, and associated equatorial plasma bubbles. Several US and Brazilian institutes deployed a broad range of instruments (all-sky imagers, digisondes, photometers, meteor/VHF radars, GPS receivers) covering a large area of Brazil. The campaign was divided in two observational phases centered on the September and October new moon periods. During these periods, an Utah State University (USU) all-sky CCD imager operated at São João d'Aliança (14.8° S, 47.6° W), near Brasilia, and a Brazilian all-sky CCD imager located at Cariri (7.4° S, 36° W), observed simultaneously the evolution of the ionospheric bubbles in the OI (630 nm) emission and the mesospheric gravity wave field. The two sites had approximately the same magnetic latitude (9–10° S) but were separated in longitude by ~1500 km. Plasma bubbles were observed on every clear night (17 from Brasilia and 19 from Cariri, with 8 coincident nights). These joint datasets provided important information for characterizing the ionospheric depletions during the campaign and to perform a novel longitudinal investigation of their variability. Measurements of the drift velocities at both sites are in good agreement with previous studies, however, the overlapping fields of view revealed significant differences in the occurrence and structure of the plasma bubbles, providing new evidence for localized generation. This paper summarizes the observed bubble characteristics important for related investigations of their seeding mechanisms associated with gravity wave activity.

scholarly journals Generation of large-scale equatorial F-region plasma depletions during lowrange spread-F season

2004 ◽  
Vol 22 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Y. Sahai ◽  
P. R. Fagundes ◽  
J. R. Abalde ◽  
A. A. Pimenta ◽  
J. A. Bittencourt ◽  
...  
Keyword(s):  
Large Scale ◽  
Ionospheric Plasma ◽  
Geomagnetic Storms ◽  
Atmospheric Composition ◽  
F Region ◽  
Range Type ◽  
June Solstice ◽  
Radio Signature ◽  
Spread F ◽  
Plasma Depletions

Abstract. All-sky imaging observations of the F-region OI 630nm nightglow emission allow us to visualize large-scale equatorial plasma depletions, generally known as trans-equatorial plasma bubbles. Strong range type spread-F is the radio signature of these (magnetically) north-south aligned plasma depletions. An extensive database of the OI 630nm emission all-sky imaging observations has been obtained at Cachoeira Paulista (22.7°S, 45.0°W; dip latitude ∼16°S), Brazil, between the years 1987 and 2000. An analysis of these observations revealed that relatively few large-scale ionospheric plasma depletions occur during the months of May to August (southern winter, June solstice) in the Brazilian sector. Of the few that are observed during these months, some occur in association with geomagnetic storms and some do not. In this paper, a detailed analysis of the events when large-scale ionospheric plasma depletions were initiated and evolved during the June solstice periods are presented and discussed.Key words. Atmospheric composition and chemistry (airglow and aurora). Ionosphere (equatorial ionosphere; ionospheric irregularities)

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