scholarly journals F-Region electron density irregularities during the development of equatorial plasma bubbles

2000 ◽  
Vol 39 (1) ◽  
pp. 117-125
Author(s):  
P. Muralikrishna
Keyword(s):  
Electron Density ◽  
Plasma Bubbles ◽  
Black Brant ◽  
F Region ◽  
Equatorial Plasma Bubbles ◽  
Electron Density Irregularities

Algunos resultados nuevos que se obtuvieron de mediciones in situ de la variación de la densidad electrónica hechas con sondas instaladas en cohetes para medir la densidad electrónica durante dos campañas que se llevaron a cabo en Alcántara (2.31° Sur 32.5° Oeste) se presentan aquí. Durante la primera campaña que se llevó a cabo en colaboración con la NASA (campaña de Iguará donde se lanzó el cohete Black Brant X el 14 de octubre de 1994) para investigar el fenómeno de los eventos de dispersión F que ocurren en altas altitudes en zonas ecuatoriales. Adicionalmente a algunos instrumentos de diagnóstico de plasma que fueron provistos por otros institutos participantes, la División de Acronomía del Instituto de Pesquisas Espaciales en Brasil, proporcionó una sonda de capacitancia de alta frecuencia que midió el perfil de alturas de la densidad electrónica. Durante la segunda campaña el cohete sonda 3 hecho en Brasil fue lanzado el 18 de diciembre de 1995. El cohete llevaba instrumentos para medir la densidad electrónica que determinaron el perfil de densidades electrónicas en la ionosfera. Algunos equipos fueron operados desde tierra para asegurarnos que los cohetes fueran lanzados en condiciones favorables para la generación de burbujas de plasma en la región F; los cohetes en ambas ocasiones atravesaron algunas burbujas de plasma en desarrollo. El espectro K de las irregularidades de plasma se obtuvo por análisis espectral de las fluctuaciones de la densidad electrónica. Las irregularidades en la densidad electrónica asociadas con las burbujas de plasma tienen líneas muy agudas en sus espectros K; estas líneas se extienden sobre un amplio rango de alturas. Lo que podría esperarse de las teorías existentes en la generación de irregularidades de pequeña escala por el proceso de cascada es un espectro K plano. Los resultados actuales podrían indicarnos la presencia de modos de onda preferidos en burbujas de plasma en desarrollo.

scholarly journals Global Climatology of Equatorial Plasma Bubbles based on GPS Radio Occultation from FormoSat-3/COSMIC

2019 ◽  
Author(s):  
Ankur Kepkar ◽  
Christina Arras ◽  
Jens Wickert ◽  
Harald Schuh ◽  
Mahdi Alizadeh ◽  
...  
Keyword(s):  
Electron Density ◽  
Radio Occultation ◽  
Signal To Noise Ratio ◽  
Global Scale ◽  
Signal To Noise ◽  
Gps Radio Occultation ◽  
Plasma Bubbles ◽  
F Region ◽  
Equatorial Plasma Bubbles ◽  
Noise Ratio

Abstract. The emerging technique of GPS Radio Occultation has been used to detect the ionospheric irregularities prominent in the F-region known as equatorial plasma bubbles. The plasma bubbles are characterized by depreciated regions of electron density. For investigating the plasma bubbles, a nine-year (2008–2016) long time series of signal-to-noise ratio data are used from the vertical GPS radio occultation profiles. The variation in the signal-to-noise ratio of the GPS signals can be linked to vertical changes in the electron density profiles that mainly occur in line with the irregularities in the Earth's ionosphere. The analysis revealed that the F-region irregularities, associated with plasma bubbles occur mainly post sunset close to Earth's geomagnetic equator. Dependence on the solar cycle as well as distinctive seasonal variation is observed when analyzed for different years. In contrast to the other ionospheric remote sensing methods, GPS Radio Occultation technique uniquely personifies the activity of the plasma bubbles based on altitude resolution on a global scale.

Strong equatorial plasma bubble associated with prominent TEC enhancement observed at mid-latitude ionosphere under the quiescent condition

2021 ◽  
Author(s):  
Fuqing Huang ◽  
Jiuhou Lei ◽  
Chao Xiong
Keyword(s):  
Electron Density ◽  
Electron Content ◽  
Radio Waves ◽  
Plasma Bubble ◽  
Total Electron ◽  
Middle Latitudes ◽  
Multiple Observations ◽  
Equatorial Plasma Bubbles ◽  
Low Latitudes

<p>Equatorial plasma bubbles (EPBs) are typically ionospheric irregularities that frequently occur at the low latitudes and equatorial regions, which can significantly affect the propagation of radio waves. In this study, we reported a unique strong EPB that happened at middle latitudes over the Asian sector during the quiescent period. The multiple observations including total electron content (TEC) from Beidou geostationary satellites and GPS, ionosondes, in-situ electron density from SWARM and meteor radar are used to explore the characteristic and mechanism of the observed EPB. The unique strong EPB was associated with great nighttime TEC/electron density enhancement at the middle latitudes, which moves toward eastward. The potential physical processes of the observed EPB are also discussed.</p>

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 Study of Equatorial Plasma Bubbles Using ASI and GPS Systems

2020 ◽  
Author(s):  
Dada P. Nade ◽  
Swapnil S. Potdar ◽  
Rani P. Pawar
Keyword(s):  
Electron Content ◽  
Gps Receiver ◽  
Plasma Bubble ◽  
Low Latitude ◽  
Total Electron ◽  
Plasma Irregularities ◽  
Plasma Bubbles ◽  
F Region ◽  
Equatorial Plasma Bubbles ◽  
Background Density

The plasma irregularities have been frequently observed in the F-region, at low latitude regions, due to the instability processes occurring in the ionosphere. The depletions in electron density, as compared to the background density, is a signature of the plasma irregularities. These irregularities are also known as the “equatorial plasma bubble” (EPB). These EPBs can measure by the total electron content (TEC) using GPS receiver and by images of the nightglow OI 630.0 nm emissions using all sky imager (ASI). The current chapter is based on the review on the signature of the EPBs in TEC and ASI. measurements. We have also discussed the importance of the study of EPBs.

Developing Equatorial Plasma Bubbles Observed by Multi-Instrument at Dawn

2021 ◽  
Author(s):  
Kun Wu ◽  
Jiyao Xu ◽  
Xinan Yue ◽  
Chao Xiong ◽  
Wenbin Wang ◽  
...  
Keyword(s):  
Southern China ◽  
Life Time ◽  
Peak Height ◽  
Global Navigation Satellite Systems ◽  
Satellite Systems ◽  
Plasma Bubbles ◽  
F Region ◽  
Equatorial Plasma Bubbles ◽  
Gnss Network ◽  
Global Navigation Satellite

<p>Previous studies have shown that equatorial plasma bubbles (EPBs) usually occur after sunset, and they usually drift eastward. Observations from an all-sky imager and the Global Navigation Satellite Systems (GNSS) network in southern China showed a special EPB event. Observational results show that the EPBs appeared near dawn and continued to develop after sunrise. They disappeared about one hour after sunrise which the life time of those EPBs exceeds 3 hours. The result provided an evidence that the EPB could develop around sunrise in optical observation. Meanwhile, those observation showed that the EPBs drifted westward, which was different from the usually eastward drifts of EPBs. The simulation from TIE-GCM model suggest that the westward drift of EPBs should be related to the enhanced westward winds at storm time. Besides, increasing in the ionospheric F region peak height was also observed near sunrise. We suggest enhance upward vertical plasma drift during geomagnetic storm plays a major role in triggering the EPBs near sunrise.</p>

scholarly journals Three-dimensional morphology of equatorial plasma bubbles deduced from measurements onboard CHAMP

2015 ◽  
Vol 33 (1) ◽  
pp. 129-135 ◽  
Author(s):  
J. Park ◽  
H. Lühr ◽  
M. Noja
Keyword(s):  
Three Dimensional ◽  
Satellite System ◽  
Low Earth Orbit ◽  
Electron Content ◽  
Total Electron ◽  
Plasma Bubbles ◽  
Equatorial Plasma Bubbles ◽  
Global Navigation Satellite ◽  
Plasma Depletion

Abstract. Total electron content (TEC) between Low-Earth-Orbit (LEO) satellites and the Global Navigation Satellite System (GNSS) satellites can be used to constrain the three-dimensional morphology of equatorial plasma bubbles (EPBs). In this study we investigate TEC measured onboard the Challenging Minisatellite Payload (CHAMP) from 2001 to 2005. We only use TEC data obtained when CHAMP passed through EPBs: that is, when in situ plasma density measurements at CHAMP altitude also show EPB signatures. The observed TEC gradient along the CHAMP track is strongest when the corresponding GNSS satellite is located equatorward and westward of CHAMP with elevation angles of about 40–60°. These elevation and azimuth angles are in agreement with the angles expected from the morphology of the plasma depletion shell proposed by Kil et al.(2009).

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