scholarly journals Topside signature of medium-scale traveling ionospheric disturbances

2014 ◽  
Vol 32 (8) ◽  
pp. 959-965 ◽  
Author(s):  
E. S. Miller ◽  
H. Kil ◽  
J. J. Makela ◽  
R. A. Heelis ◽  
E. R. Talaat ◽  
...  
Keyword(s):  
Electric Fields ◽  
Dissociative Recombination ◽  
Middle Latitude ◽  
Topside Ionosphere ◽  
Ionospheric Disturbances ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances ◽  
Periodic Groups ◽  
In Situ Sensors

Abstract. Plasma blobs, localized plasma density enhancements that occur singularly or in periodic groups, have been observed by in situ sensors in the lower- and middle-latitude nighttime ionosphere. Traditionally, creation of blobs has been thought to be connected to equatorial plasma bubbles, which are localized plasma depletions. Here, we report the association of blobs with medium-scale traveling ionospheric disturbances (MSTIDs). On 17 January 2010, an all-sky imager on the Caribbean island of Bonaire (geographic: 12.190° N, 68.244° W; geomagnetic 22.46° N, 7.099° E) observed a nighttime electrified MSTID propagating to the southwest. At the time of the MSTID's transit, the Coupled Ion-Neutral Dynamics Investigation instrument onboard the Communication/Navigation Outage Forecasting System satellite detected a group of blobs along the same geomagnetic flux tubes. The electron density variations measured at the satellite altitude, indicating the blobs, are anticorrelated with the intensity variations of the 630.0 nm dissociative recombination emission measured on the same magnetic field lines. This relationship is explained by a modulation of the O+ profile altitude due to electric fields generated within the MSTID. This idea is supported by in situ measurements of the vertical ion velocity. We argue that common climatology between blobs and MSTIDs reported in the literature, as well as this coincident observation, suggest that blobs may be the in situ signature of MSTIDs in the topside ionosphere.

scholarly journals Numerical modeling of the disappearance of equatorial plasma bubble by nighttime medium-scale traveling ionospheric disturbances

2021 ◽  
Author(s):  
Min-Yang Chou ◽  
Charles C. H. Lin ◽  
Joseph D. Huba
Keyword(s):  
Electric Fields ◽  
Induce Polarization ◽  
Underlying Mechanism ◽  
Naval Research ◽  
Ionospheric Disturbances ◽  
Plasma Bubble ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances ◽  
Ionosphere Model ◽  
Meridional Winds

Abstract The Naval Research Laboratory first-principles ionosphere model SAMI3/ESF is performed to study the interaction between the nighttime medium-scale traveling ionospheric disturbances (MSTIDs) and equatorial plasma bubbles (EPBs). The synthetic dynamo currents are imposed into the potential equation to induce polarization electric fields for generating the MSTIDs. Simulations demonstrate that the MSTIDs can inhibit the upward growth of EPBs; however, MSTIDs alone are insufficient to explain the disappearance of EPBs. We found that the meridional winds likely contribute to the disappearance of MSTIDs by reducing the background electron density and polarization electric fields within the EPBs. Then, the MSTIDs transport plasma to fill the EPB depletions up via E × B drifts. Both MSTIDs and meridional winds are necessary to comprehend the underlying mechanism of EPB disappearance. We also found that the zonal and vertical E × B drifts within the MSTIDs affect the morphology of EPBs, leading to a reverse-C shape structure.

scholarly journals Numerical Modeling of the Disappearance of Equatorial Plasma Dubble by the Nighttime Medium-scale Traveling Ionospheric Disturbances

2020 ◽  
Author(s):  
Min-Yang Chou ◽  
Charles C. H. Lin ◽  
Joseph D. Huba
Keyword(s):  
Electric Fields ◽  
Induce Polarization ◽  
Underlying Mechanism ◽  
Naval Research ◽  
Ionospheric Disturbances ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances ◽  
Ionosphere Model ◽  
Equatorial Plasma Bubbles ◽  
Meridional Winds

Abstract The Naval Research Laboratory first-principles ionosphere model SAMI3/ESF is performed to study the interaction between the nighttime medium-scale traveling ionospheric disturbances (MSTIDs) and equatorial plasma bubbles (EPBs). The synthetic Es layer instability driven by the external dynamo currents are imposed into the potential equation to induce polarization electric fields for generating the MSTIDs. Simulations demonstrate that the MSTIDs alone can inhibit the upward growth of EPBs, but are insufficient to explain the disappearance of EPBs. The meridional winds are necessary to comprehend the underlying mechanism. The zonal and vertical E × B drifts of MSTIDs also affect the morphology of EPBs that could result in a reverse-C shape structure.

scholarly journals Statistical study of medium-scale traveling ionospheric disturbances in low-latitude ionosphere using an automatic algorithm

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Pin-Hsuan Cheng ◽  
Charles Lin ◽  
Yuichi Otsuka ◽  
Hanli Liu ◽  
Panthalingal Krishanunni Rajesh ◽  
...  
Keyword(s):  
Climate Model ◽  
Geomagnetic Latitude ◽  
Detection Algorithm ◽  
Support Vector ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Low Latitude ◽  
Total Electron ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances

AbstractThis study investigates the medium-scale traveling ionospheric disturbances (MSTIDs) statistically at the low-latitude equatorial ionization anomaly (EIA) region in the northern hemisphere. We apply the automatic detection algorithm including the three-dimensional fast Fourier transform (3-D FFT) and support vector machine (SVM) on total electron content (TEC) observations, derived from a network of ground-based global navigation satellite system (GNSS) receivers in Taiwan (14.5° N geomagnetic latitude; 32.5° inclination), to identify MSTID from other waves or irregularity features. The obtained results are analyzed statistically to examine the behavior of low-latitude MSTIDs. Statistical results indicate the following characteristics. First, the southward (equatorward) MSTIDs are observed almost every day during 0800–2100 LT in Spring and Winter. At midnight, southward MSTIDs are more discernible in Summer and majority of them are propagating from Japan to Taiwan. Second, northward (poleward) MSTIDs are more frequently detected during 1200–2100 LT in Spring and Summer with the secondary peak of occurrence between day of year (DOY) 100–140 during 0000–0300 LT. The characteristics of the MSTIDs are interpreted with additional observations from radio occultation (RO) soundings of FORMOSAT-3/COSMIC as well as modeled atmospheric waves from the high-resolution Whole Atmosphere Community Climate Model (WACCM) suggesting that the nighttime MSTIDs in Summer is likely connected to the atmospheric gravity waves (AGWs).

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