Comparing plasma bubble occurrence rates at CHAMP and GRACE altitudes during high and low solar activity

Abstract. Based on the multi-year data base (2001–2009) of CHAMP Planar Langmuir Probe (PLP) data and GRACE K-Band Ranging (KBR1B) data, typical features of ionospheric plasma irregularities are studied at the altitudes of CHAMP (300–400 km) and GRACE (~500 km). The phenomena we are focusing on are the equatorial plasma bubbles (EPBs). Similar seasonal/longitudinal (S/L) distributions of EPB have been found at both CHAMP and GRACE altitudes during solar active and quiet years. Peak EPB occurrence rates, defined as number of events within an S/L bin divided by the number of passes over that bin, decrease from the high and moderate solar flux period (2001–2005) to the low solar flux period (2005–2009) from 80% to 60% and 60% to 40% at CHAMP and GRACE altitudes, respectively. On average the occurrence rate increases linearly with solar flux at about the same rate at CHAMP and GRACE. For high flux levels (P10.7>200) non-linear increases are observed at GRACE. The occurrence rate increases rapidly after 19:00 local time (LT) during high solar flux periods. Around solar minimum rates increase more gently and peak around 22:00 LT. The highest occurrence rates are encountered at latitudes around 10° north and south of the dip equator. Results from the two altitudes support the notion that EPBs form regions of depleted plasma along geomagnetic fluxtubes. It is shown for the first time that in regions of high occurrence rates EPBs are associated with fluxtubes reaching greater apex heights than those in regions of low rates.

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Study of Equatorial Plasma Bubbles Using ASI and GPS Systems

Geographic Information Systems in Geospatial Intelligence ◽

10.5772/intechopen.85604 ◽

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.

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Filamentary Alfvénic structures excited at the edges of equatorial plasma bubbles

Annales Geophysicae ◽

10.5194/angeo-25-2159-2007 ◽

2007 ◽

Vol 25 (10) ◽

pp. 2159-2165 ◽

Cited By ~ 11

Author(s):

R. Pottelette ◽

M. Malingre ◽

J. J. Berthelier ◽

E. Seran ◽

M. Parrot

Keyword(s):

Alfven Waves ◽

Alfvén Waves ◽

Plasma Bubble ◽

Plasma Bubbles ◽

Wave Measurements ◽

Demeter Satellite ◽

Equatorial Plasma Bubbles ◽

Background Magnetic Field ◽

Gravity Driven ◽

Displacement Currents

Abstract. Recent observations performed by the French DEMETER satellite at altitudes of about 710 km suggest that the generation of equatorial plasma bubbles correlates with the presence of filamentary structures of field aligned currents carried by Alfvén waves. These localized structures are located at the bubble edges. We study the dynamics of the equatorial plasma bubbles, taking into account that their motion is dictated by gravity driven and displacement currents. Ion-polarization currents appear to be crucial for the accurate description of the evolution of plasma bubbles in the high altitude ionosphere. During their eastward/westward motion the bubbles intersect gravity driven currents flowing transversely with respect to the background magnetic field. The circulation of these currents is prohibited by large density depressions located at the bubble edges acting as perfect insulators. As a result, in these localized regions the transverse currents have to be locally closed by field aligned currents. Such a physical process generates kinetic Alfvén waves which appear to be stationary in the plasma bubble reference frame. Using a two-dimensional model and "in situ" wave measurements on board the DEMETER spacecraft, we give estimates for the magnitude of the field aligned currents and the associated Alfvén fields.

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Occurrence climatology of equatorial plasma bubbles derived using FormoSat-3 ∕ COSMIC GPS radio occultation data

Annales Geophysicae ◽

10.5194/angeo-38-611-2020 ◽

2020 ◽

Vol 38 (3) ◽

pp. 611-623

Author(s):

Ankur Kepkar ◽

Christina Arras ◽

Jens Wickert ◽

Harald Schuh ◽

Mahdi Alizadeh ◽

...

Keyword(s):

Solar Activity ◽

Radio Occultation ◽

Signal To Noise Ratio ◽

Strong Dependence ◽

Occurrence Rate ◽

High Solar Activity ◽

Altitudinal Distribution ◽

Plasma Bubbles ◽

Ionosphere Plasma ◽

Equatorial Plasma Bubbles

Abstract. The Global Positioning System – Radio Occultation (GPS-RO) observations from FormoSat-3 ∕ COSMIC are used to comprehend the global distribution of equatorial plasma bubbles which are characterized by depletion regions of plasma in the F region of the ionosphere. Plasma bubbles that cause intense scintillation of the radio signals are identified based on the S4 index derived from the 1 Hz raw signal-to-noise ratio measurements between 2007 and 2017. The analyses revealed that bubbles influenced by background plasma density occurred along the geomagnetic equator and had an occurrence peak around the dip equator during high solar activity. The peak shifted between the African and American sectors, depending on different solar conditions. Plasma bubbles usually developed around 19:00 local time (LT), with maximum occurrence around 21:00 LT during solar maximum and ∼22:00 LT during solar minimum. The occurrence of bubbles showed a strong dependence on longitudes, seasons, and solar cycle with the peak occurrence rate in the African sector around the March equinox during high solar activity, which is consistent with previous studies. The GPS-RO technique allows an extended analysis of the altitudinal distribution of global equatorial plasma bubbles obtained from high vertical resolution profiles, thus making it a convenient tool which could be further used with other techniques to provide a comprehensive view of such ionospheric irregularities.

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Characteristics of ionospheric irregularities near the northern equatorial anomaly crest

10.5194/angeo-2019-64 ◽

2019 ◽

Author(s):

Jinghua Li ◽

Guanyi Ma ◽

Klemens Hocke ◽

Qingtao Wan ◽

Jiangtao Fan ◽

...

Keyword(s):

Seasonal Variations ◽

Ionospheric Irregularities ◽

Lower Latitude ◽

Occurrence Rate ◽

Electron Content ◽

Plasma Bubble ◽

Equatorial Anomaly ◽

Total Electron ◽

Latitude Belt ◽

Plasma Bubbles

Abstract. This paper detects the ionospheric irregularities with rate of total electron content (TEC) change index, ROTI from GPS observation at Taoyuan (24.95° N, 121.16° E) for the solar medium and minimum years of 2003 and 2008 in the declining phase of cycle 23, the solar maximum of 2014 in solar cycle 24. Local occurrence rate (LOR) is proposed to clarify the characteristics of the irregularities together with monthly occurrence rate (MOR) and ROTI maximum for 3 latitude belts, 20–23° N, 23–26° N, 26–29° N, around the equatorial anomaly crest. MOR in May/June is larger than those in equinoxes in 2008 and 2003, which is different from that of equatorial plasma bubbles. In 2014 although MOR maximum is observed in equinoxes, the MOR in May and June is much larger than that in September. Moreover, MORs in May to August at higher latitude belt 26–29° N are larger than those in lower latitude belts and smaller in the equinoxes. The latitudinal dependence of the LORs tends to be similar to that of MORs. Seasonal variations of LORs have a similar trend for different solar activities. Maximum LORs are observed in Feb/Mar and Sep/Oct, and moderate around June, which resemble those of plasma bubbles in seasonal variations, except for latitude belt 26–29° N where maximum LORs are seen in May–Jul. The seasonal variation of ROTI maximum conforms to that of the LOR. The results suggest that irregularities near the crest in May to August are mainly originated from nonequatorial process, which is more frequently happened but weaker than plasma bubble in both spatiotemporal scale and strength.

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Dynamics Ionospheric Plasma Bubbles Measured by Optical Imaging System

Journal of Institute of Science and Technology ◽

10.3126/jist.v20i1.13906 ◽

2015 ◽

Vol 20 (1) ◽

pp. 20-27

Author(s):

Narayan P. Chapagain

Keyword(s):

Imaging System ◽

Equatorial Ionosphere ◽

Navigation Systems ◽

Plasma Bubble ◽

Central Pacific ◽

Central Pacific Ocean ◽

Plasma Bubbles ◽

Christmas Island ◽

Equatorial Plasma Bubbles ◽

Plasma Depletions

Deep plasma depletions during the nighttime period in the equatorial ionosphere (referred to as equatorial plasma bubbles –EPBs) can significantly affect communications and navigation systems. In this study, we present the image measurements of plasma bubble from Christmas Island (2.1°N, 157.4°W, dip latitude 2.8°N) in the central Pacific Ocean. These observations were made during September-October 1995 using a Utah State University (USU) CCD imaging system measured at ~280 km altitude. Well-defined magnetic field-aligned plasma depletions were observed for 18 nights, including strong post-midnight fossilized structures, enabling detailed measurements of their morphology and dynamics. We also estimate zonal velocity of the plasma bubbles from available images. The zonal drift velocity of the EPBs is a very important parameter for the understanding and modeling of the electrodynamics of the equatorial ionosphere and for the predictions of ionospheric irregularities. The eastward zonal drift velocities were around 90-100 m/s prior to local midnight, and decreases during the post-midnight period that persisted until dawn.Journal of Institute of Science and Technology, 2015, 20(1): 20-27

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Equatorial F-region plasma depletion drifts: latitudinal and seasonal variations

Annales Geophysicae ◽

10.5194/angeo-21-2315-2003 ◽

2003 ◽

Vol 21 (12) ◽

pp. 2315-2322 ◽

Cited By ~ 35

Author(s):

A. A. Pimenta ◽

P. R. Fagundes ◽

Y. Sahai ◽

J. A. Bittencourt ◽

J. R. Abalde

Keyword(s):

Large Scale ◽

Ionospheric Irregularities ◽

Plasma Bubble ◽

Plasma Irregularities ◽

Optical Instruments ◽

Plasma Bubbles ◽

F Region ◽

Variation Characteristics ◽

Wind Velocities ◽

Region Plasma

Abstract. The equatorial ionospheric irregularities have been observed in the past few years by different techniques (e.g. ground-based radar, digisonde, GPS, optical instruments, in situ satellite and rocket instrumentation), and its time evolution and propagation characteristics can be used to study important aspects of ionospheric dynamics and thermosphere-ionosphere coupling. At present, one of the most powerful optical techniques to study the large-scale ionospheric irregularities is the all-sky imaging photometer system, which normally measures the strong F-region nightglow 630 nm emission from atomic oxygen. The monochromatic OI 630 nm emission images usually show quasi-north-south magnetic field-aligned intensity depletion bands, which are the bottomside optical signatures of large-scale F-region plasma irregularities (also called plasma bubbles). The zonal drift velocities of the plasma bubbles can be inferred from the space-time displacement of the dark structures (low intensity regions) seen on the images. In this study, images obtained with an all-sky imaging photometer, using the OI 630 nm nightglow emission, from Cachoeira Paulista (22.7° S, 45° W, 15.8° S dip latitude), Brazil, have been used to determine the nocturnal monthly and latitudinal variation characteristics of the zonal plasma bubble drift velocities in the low latitude (16.7° S to 28.7° S) region. The east and west walls of the plasma bubble show a different evolution with time. The method used here is based on the western wall of the bubble, which presents a more stable behavior. Also, the observed zonal plasma bubble drift velocities are compared with the thermospheric zonal neutral wind velocities obtained from the HWM-90 model (Hedin et al., 1991) to investigate the thermosphere-ionosphere coupling. Salient features from this study are presented and discussed.Key words. Ionosphere (ionosphere-atmosphere interactions; ionospheric irregularities; instruments and techniques)

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Analysis of the seasonal variations of equatorial plasma bubble occurrence observed from Haleakala, Hawaii

Annales Geophysicae ◽

10.5194/angeo-22-3109-2004 ◽

2004 ◽

Vol 22 (9) ◽

pp. 3109-3121 ◽

Cited By ~ 58

Author(s):

J. J. Makela ◽

B. M. Ledvina ◽

M. C. Kelley ◽

P. M. Kintner

Keyword(s):

Optical Data ◽

Data Sets ◽

Maximum Probability ◽

Plasma Bubble ◽

Active Growth ◽

Seasonal Trends ◽

Plasma Bubbles ◽

Gps Scintillation ◽

Equatorial Plasma Bubbles ◽

The Pacific

Abstract. Over 300 nights of airglow and GPS scintillation data collected between January 2002 and August 2003 (a period near solar maximum) from the Haleakala Volcano, Hawaii are analyzed to obtain the seasonal trends for the occurrence of equatorial plasma bubbles in the Pacific sector (203° E). A maximum probability for bubble development is seen in the data in April (45%) and September (83%). A broad maximum of occurrence is seen in the data from June to October (62%). Many of the bubbles observed from June through August occur later in the evening, and, as seen in the optical data, tend to be "fossilized". This suggests that the active growth region during these months is to the west of the observing location. These seasonal trends are consistent with previous data sets obtained both from other ground-based and satellite studies of the occurrence of equatorial bubbles in the Pacific sector. However, our data suggests a much greater probability of bubble occurrence than is seen in other data sets, with bubbles observed on over 40% of the nights studied.

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Airglow observations over the equatorial ionization anomaly zone in Taiwan

Annales Geophysicae ◽

10.5194/angeo-29-749-2011 ◽

2011 ◽

Vol 29 (5) ◽

pp. 749-757 ◽

Cited By ~ 7

Author(s):

J. Y. Liu ◽

P. K. Rajesh ◽

I. T. Lee ◽

T. C. Chow

Keyword(s):

Global Positioning System ◽

Ionospheric Disturbances ◽

Iri Model ◽

Plasma Bubbles ◽

Equatorial Ionization Anomaly ◽

Equatorial Plasma Bubbles ◽

Global Positioning ◽

Plasma Depletions ◽

First Time ◽

Eastern Wall

Abstract. Airglow imaging at mid-latitude stations often show intensity modulations associated with medium scale travelling ionospheric disturbances (MSTID), while those carried out near the equatorial regions reveal depletions caused by equatorial plasma bubbles (EPB). Two all sky cameras are used to observe plasma depletions in the 630.0 nm emission over the equatorial ionization anomaly (EIA) region, Taiwan (23° N, 121° E; 13.5° N Magnetic) during 1998–2002 and 2006–2007. The results show EPB and MSTID depletions in different solar activity conditions. Several new features of the EPB depletions such as bifurcation, secondary structure on the walls, westward tilt, etc., are discussed in this paper. Evidence of tilted depletions with secondary structures developing on the eastern wall that later evolve to appear as bifurcations, are presented for the first time. Moreover, detail investigations are carried out using International Reference Ionosphere (IRI) model as well as the electron density from Ionosonde and Global Positioning System (GPS) Occultation Experiment (GOX) onboard FORMOSAT-3/COSMIC satellite, to understand the conditions that favor the propagation of MSTID to the latitude of Taiwan.

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The study of equatorial plasma bubble during January to April 2012 over Kolhapur (India)

Annals of Geophysics ◽

10.4401/ag-6868 ◽

2016 ◽

Vol 59 (2) ◽

Author(s):

Parashram T. Patil ◽

Rupesh N. Ghodpage ◽

Alok K. Taori ◽

Rohit P. Patil ◽

Subramanian Gurubaran ◽

...

Keyword(s):

Magnetic Field ◽

Emission Line ◽

Drift Velocity ◽

Velocity Variation ◽

Plasma Bubble ◽

Low Latitude ◽

Plasma Bubbles ◽

F Region ◽

Equatorial Plasma Bubbles ◽

Observation Period

Over 53 nights of all sky airglow imager data collected during January-April 2012 from the low latitude station Kolhapur (16.68°N, 74.26°E; 10.6°N dip latitude) have been analyzed to study the F-region dynamics through the imaging of OI 630 nm emission line. The observed night airglow data were supported by the ionosonde measurements from Tirunelveli (8.7°N, 77.8°E; 0.51°N dip latitude). Well defined magnetic field aligned depletions were observed during the observation period. Out of 53 nights, 40 nights exhibited the occurrence of north-south aligned equatorial plasma bubbles. These plasma bubbles were found moving towards east with drift speed in range between 70 to 200 m s-1. We have analyzed the zonal drift velocity variation and relation of bubble occurrence with the base height of the ionosphere together with the effects of the geomagnetic Ap and solar flux F10.7 cm index in its first appearance.

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Occurrence climatology of equatorial plasma bubbles (EPBs) using optical observations over Kolhapur, India during solar cycle-24

Annals of Geophysics ◽

10.4401/ag-8068 ◽

2020 ◽

Vol 63 (6) ◽

Author(s):

Onkar Gurav ◽

Rupesh Ghodpage ◽

Parashram Patil ◽

Sripathi Samireddipalle ◽

Ashok Sharma ◽

...

Keyword(s):

Solar Activity ◽

Solar Cycle ◽

Optical Observations ◽

Occurrence Rate ◽

High Solar Activity ◽

Storm Events ◽

Plasma Bubbles ◽

Equatorial Plasma Bubbles ◽

Solar Cycle 24 ◽

Cycle 24

In this paper, the occurrence characteristics of the equatorial plasma bubbles (EPBs) using OI 630.0 nm all sky imager (ASI) night airglow observations over Kolhapur (16.8o N, 74.2o E, 10.6o dip. Lat.) during the solar cycle-24 are presented. These results are discussed in terms of season, solar and magnetic activity during years 2011 to 2018. The ASI observations were only carried out during January to May and October to December months due to unfavorable weather conditions. The results suggest that while January, February and December are the only months where EPBs were found to occur over Kolhapur in any year, but the percentage of occurrence of EPBs during these months suggests their low occurrence rate during solar minimum. A total of 683 nights of observations were carried, out of which, 93 nights are found to be magnetically disturbed nights having Ap>18. In addition, the ASI observations are also correlated with Pre-Reversal Enhancement of the vertical drift of the evening sector at Tirunelveli on few storm events for comparison. The important findings of this study are: 1) increase in the occurrence of EPBs with respect to the solar activity; 2) suppression of EPBs on 71 disturbed nights, while enhancement of EPBs on 22 nights under magnetic disturbance; 3) EPBs occurrence during equinox months is found to be higher than winter months during ascending phase of solar cycle-24.; and, 4) EPBs are mostly observed in the pre-midnight sector in the high solar activity (HSA) period, while they are seen in the post-midnight to dawn sector during the low solar activity (LSA) period. We also noticed non-occurrence of EPBs during equinox month in the year 2018 which seems to be peculiar and needs further investigations.

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