Scale analysis of equatorial plasma irregularities derived from Swarm constellation

Xiong, Chao; Stolle, Claudia; Lühr, H.; Park, Jaeheung; Fejer, Bela G.; Kervalishvili, Guram

doi:10.1186/s40623-016-0502-5

Cited by 59 publications

(84 citation statements)

References 32 publications

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“…Since these irregularities often exist inside plasma bubbles, they have long been regarded as indications for EPBs (Abdu et al, 2003;Basu et al, 1980;Demyanov et al, 2012;Lühr et al, 2014;Ma & Maruyama, 2006;Park et al, 2005;Rama Rao et al, 2009;Rodrigues et al, 2009;Xiong et al, 2016;Yizengaw et al, 2013;Yokoyama et al, 2007). Since these irregularities often exist inside plasma bubbles, they have long been regarded as indications for EPBs (Abdu et al, 2003;Basu et al, 1980;Demyanov et al, 2012;Lühr et al, 2014;Ma & Maruyama, 2006;Park et al, 2005;Rama Rao et al, 2009;Rodrigues et al, 2009;Xiong et al, 2016;Yizengaw et al, 2013;Yokoyama et al, 2007).…”

Section: Data and Analysis Methodsmentioning

confidence: 99%

“…Plasma blobs are frequently observed in crest regions of the equatorial ionization anomaly (EIA) at altitudes above~250 km (Kil et al, 2011;Le et al, 2003;Park, Stolle, et al, 2008;Pimenta et al, 2004Pimenta et al, , 2007Tardelli-Coelho et al, 2017). EPBs have been detected in situ by many satellites at different heights such as ROCSAT, C/NOFS, CHAMP, DMSP, SWARM, and others (Huang et al, 2014;Le et al, 2003;Xiong et al, 2016). Since the percentage increase in density may depend on plasma flow in the vicinity of the blob, there is no clear threshold of percentage increase in density for blob identification, and density enhancement with different percentage has been used in previous studies.…”

Section: Introductionmentioning

confidence: 99%

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Plasma Blobs Concurrently Observed With Bubbles in the Asian‐Oceanian Sector During Solar Maximum

et al. 2019

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With simultaneous ionospheric measurements from ROCSAT‐1 satellite and ground ionosondes/GPS receivers, three cases of concurrent plasma blobs and bubbles in the same magnetic meridian were observed around 22:30 LT in Asian‐Oceanian sector during solar maximum. Two cases were observed: equatorial spread F (ESF) over Vanimo station (geog. 2.7°S, 141.3°E; geom. 11.2°S, 146.2°W) and plasma blobs around 8.0°S (geom.) on 1 June and 6 October 2003. The other case observed equatorial spread F over Hainan station (geog. 19.5°N, 109.1°E; geom. 9.1°N, 179.1°W) and plasma blob near the dip equator on 8 March 2004. Plasma blobs were all observed near 600‐km height near the equator. Equatorial spread F and amplitude scintillations from the ground stations were observed near the same magnetic meridian, indicating the existence of bubbles. Considering that both plasma bubbles and blobs are field‐aligned elongated structures, magnetic field line mapping shows that in the two cases at Vanimo, blobs were above bubbles, providing direct observational evidence for blob formation in the intermediate stage of plasma bubble evolution; in the case at Hainan, the blob and bubble were likely at similar height, and it could be generated by gravity wave.

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Section: Data and Analysis Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Plasma Blobs Concurrently Observed With Bubbles in the Asian‐Oceanian Sector During Solar Maximum

et al. 2019

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“…It is generally accepted that EPBs are triggered under a favorable condition of the generalized Rayleigh-Taylor (R-T) instability at the bottomside of the F layer, where a steep vertical density gradient forms after the E layer disappears postsunset due to high recombination rate. Furthermore, the temporal variation and occurrence distribution of irregularities/bubbles can be extracted from in situ satellite observations, such as the Defense Meteorological Satellite Program constellation Huang et al, 2002), Communications/Navigation Outrage Forecasting System (C/NOFS) satellite (Huang et al, 2014;Smith & Heelis, 2017), and Swarm constellation (Xiong et al, 2016;Zakharenkova et al, 2016). For example, the structure of EPBs can be observed from irregular traces of range-type equatorial spread F in ionograms (Abdu, 2012;Hysell, 2000;Li et al, 2018;Tsunoda, 2015).…”

Section: Introductionmentioning

confidence: 99%

Coordinated Ground‐Based and Space‐Based Observations of Equatorial Plasma Bubbles

Zou

Eastes

et al. 2020

JGR Space Physics

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This paper presents coordinated and fortuitous ground-based and spaceborne observations of equatorial plasma bubbles (EPBs) over the South American area on 24 October 2018, combining the following measurements: Global-scale Observations of Limb and Disk far ultraviolet emission images, Global Navigation Satellite System total electron content data, Swarm in situ plasma density observations, ionosonde virtual height and drift data, and cloud brightness temperature data. The new observations from the Global-scale Observations of Limb and Disk/ultraviolet imaging spectrograph taken at geostationary orbit provide a unique opportunity to image the evolution of plasma bubbles near the F peak height over a large geographic area from a fixed longitude location. The combined multi-instrument measurements provide a more integrated and comprehensive way to study the morphological structure, development, and seeding mechanism of EPBs. The main results of this study are as follows: (1) The bubbles developed a westward tilted structure with 10-15 • inclination relative to the local geomagnetic field lines, with eastward drift velocity of 80-120 m/s near the magnetic equator that gradually decreased with increasing altitude/latitude. (2) Wave-like oscillations in the bottomside F layer and detrended total electron content were observed, which are probably due to upward propagating atmospheric gravity waves. The wavelength based on the medium-scale traveling ionospheric disturbance signature was consistent with the interbubble distance of ∼500-800 km. (3) The atmospheric gravity waves that originated from tropospheric convective zone are likely to play an important role in seeding the development of this equatorial EPBs event.Plain Language Summary This study presents multi-instrument observations of equatorial plasma density depletions occurred on 24 October 2018 by using Global-scale Observations of Limb and Disk far ultraviolet images, Global Navigation Satellite System total electron content data, electron density measurements from Swarm satellite, ionosonde measurements, and cloud temperature data. This multi-instrument study generated an integrated and detailed image revealing both large-scale and mesoscale structures of the equatorial plasma depletion. Our results also suggest that atmospheric gravity waves originating from tropospheric convection activity could play a significant seeding role in the development of equatorial plasma bubbles. Key Points: • Combined GOLD/UV spectrograph images and ground-based TEC data revealed EPB features and development over a large geographic area • Bottomside F layer oscillations and traveling ionospheric disturbance were observed by ionosonde and detrended TEC results • Atmospheric gravity waves likely play an important role in seeding the R-T instability and the development of this EPB event Correspondence to: E. Aa,

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“…Figure 4a shows such an example at high latitudes. The original 2 Hz electron density data measured by the Langmuir probe is plotted with a black line, and a filter has been applied to the original data series for filtering out irregularities with scale lengths of less than 120 km along track, following the work of Xiong et al (2016b). From the filtered data (red line) we then find all depleted regions, and the peak values between two depleted regions are then recorded from the original 2 Hz data series (marked with green squares).…”

Section: Gps Signal Loss Event Detectionmentioning

confidence: 99%

Climatology of GPS signal loss observed by Swarm satellites

2018

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Abstract. By using 3-year global positioning system (GPS) measurements from December 2013 to November 2016, we provide in this study a detailed survey on the climatology of the GPS signal loss of Swarm onboard receivers. Our results show that the GPS signal losses prefer to occur at both low latitudes between ±5 and ±20 • magnetic latitude (MLAT) and high latitudes above 60 • MLAT in both hemispheres. These events at all latitudes are observed mainly during equinoxes and December solstice months, while totally absent during June solstice months. At low latitudes the GPS signal losses are caused by the equatorial plasma irregularities shortly after sunset, and at high latitude they are also highly related to the large density gradients associated with ionospheric irregularities. Additionally, the highlatitude events are more often observed in the Southern Hemisphere, occurring mainly at the cusp region and along nightside auroral latitudes. The signal losses mainly happen for those GPS rays with elevation angles less than 20 • , and more commonly occur when the line of sight between GPS and Swarm satellites is aligned with the shell structure of plasma irregularities. Our results also confirm that the capability of the Swarm receiver has been improved after the bandwidth of the phase-locked loop (PLL) widened, but the updates cannot radically avoid the interruption in tracking GPS satellites caused by the ionospheric plasma irregularities. Additionally, after the PLL bandwidth increased larger than 0.5 Hz, some unexpected signal losses are observed even at middle latitudes, which are not related to the ionospheric plasma irregularities. Our results suggest that rather than 1.0 Hz, a PLL bandwidth of 0.5 Hz is a more suitable value for the Swarm receiver.

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Scale analysis of equatorial plasma irregularities derived from Swarm constellation

Cited by 59 publications

References 32 publications

Plasma Blobs Concurrently Observed With Bubbles in the Asian‐Oceanian Sector During Solar Maximum

Plasma Blobs Concurrently Observed With Bubbles in the Asian‐Oceanian Sector During Solar Maximum

Coordinated Ground‐Based and Space‐Based Observations of Equatorial Plasma Bubbles

Climatology of GPS signal loss observed by Swarm satellites

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