Discovery of a low-latitude ionospheric trough associated with the inner radiation belt

Karpachev, A. T.

doi:10.1038/s41598-021-87356-y

Cited by 3 publications

(6 citation statements)

References 31 publications

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“…Statistical analysis also confirmed that the RIT is more often formed at the longitudes of America, as suggested in a recent study (Karpachev, 2021b). This is because the precipitation of energetic particles occurs most intensively at longitudes with a weak geomagnetic field.…”

Section: Discussionsupporting

confidence: 85%

“…This is a typical situation for almost any storm. We also noted another low‐latitude trough during pass 25 on December 28, 2002, which was discovered and described earlier in (Karpachev, 2021b).…”

Section: Longitudinal Variations In Rit Position and Occurrence Proba...supporting

confidence: 84%

“…The upper panels in Figure 8 show that in the Southern hemisphere, the RIT is observed more than 1.5 times as often as that in the Northern hemisphere. In both the hemispheres, the RIT is most often formed at the longitudes of America, as suggested in a recent study (Karpachev, 2021b). This is because the precipitation of energetic particles occurs most intensively at the longitudes with a weak geomagnetic field.…”

Section: Longitudinal Variations In Rit Position and Occurrence Proba...supporting

confidence: 68%

“…Therefore, it should be expected that the RIT is also observed at the same latitudes. Finally, the relation between the appearance of the RIT and the longitude was revealed (Karpachev, 2021b) and variations in the RIT position with respect to the longitude were observed (Karpachev, 2021a). These not-well-understood issues determine the purpose of this paper, that is, to investigate diurnal, latitudinal, and longitudinal variations in the RIT position and occurrence probability, as well as the dependence of its position on the geomagnetic activity indices (Kp and Dst), based on a large CHAMP satellite dataset.…”

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confidence: 98%

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Statistical Analysis of Ring Ionospheric Trough Characteristics

Karpachev

2021

JGR Space Physics

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The decay of the magnetospheric ring current during geomagnetic disturbances is associated with numerous processes. Particle precipitation is related to Coulomb collisions and ion-cyclotron instability owing to the interaction of hot protons of the ring current and cold particles of the outer plasmasphere (Cole, 1975;Cornwall et al., 1971). This decay tends to occur in the recovery phase of the geomagnetic disturbance when the expanding plasmasphere overlaps with the low-latitude fraction of the ring current. In other words, the most intense decay of the ring current occurs at the latitudes of the plasmapause. The precipitation of hot particles and heat flow owing to thermal conductivity, directed along the lines of the force, heat the ionosphere at the heights of the F2 layer. Because of ionospheric heating, an intense electron temperature (Te) peak and a stable auroral red (SAR) arc are formed (Hoch, 1973;Ievenko & Alekseev, 2004;Kozyra et al., 1986). The heating of the ionosphere also increases the recombination, inducing the formation of an ionization trough (Pavlov, 1996). Thus, the plasmapause, Te peak, SAR arc, and ionospheric trough are interrelated structures, at least during the recovery phase of a storm/substorm.

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Section: Discussionsupporting

confidence: 85%

Section: Longitudinal Variations In Rit Position and Occurrence Proba...supporting

confidence: 84%

Section: Longitudinal Variations In Rit Position and Occurrence Proba...supporting

confidence: 68%

mentioning

confidence: 98%

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Statistical Analysis of Ring Ionospheric Trough Characteristics

Karpachev

2021

JGR Space Physics

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“…During the recovery phase on the night of 13 October (DOY = 286), a larger depletion region emerges at lower latitudes that is around 15° wide in latitude with an equatorward edge at ∼30°N that is quite sharp. It is possible that this is a combination of multiple lower latitude troughs (e.g., A. T. Karpachev (2021)) whose boundaries have merged/blurred. However, this is purely conjecture given the lack of definitive features along the latitude direction within the TEC data.…”

Section: Data and Analysismentioning

confidence: 99%

Irregularities Observed at the Edge of a Mid‐Latitude Ionospheric Depletion Following a Geomagnetic Storm

Helmboldt

2023

Space Weather

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This manuscript presents the analysis of data from multiple ground‐ and space‐based sensors in the North American region before, during, and after the 12 October 2021 geomagnetic storm. Total electron content (TEC) and electron density data show the formation and equatorward propagation of a mid‐latitude trough at ∼50°N followed by the appearance of a wider depletion region (∼15° in latitude) at lower latitudes. During the recovery phase on the 13th, the equatorward edge of this depletion region settled at around 30° latitude and exhibited a steep density gradient. By the 14th, this sharp boundary had disappeared. Near this edge on the 13th, small‐scale irregularities formed. The impact of these was observed within Global Positioning System data as elevated rate of TEC index (ROTI) and presented as strong 35 MHz scintillations of cosmic radio sources as well as spread‐F within ionograms from multiple digisonde systems. GPS and 35‐MHz data demonstrated that the irregularity region was narrowly confined (≲5° wide) near the edge of the depletion region. The 35‐MHz scintillation data also showed that the irregularities were moving relatively slowly at ∼7 m s−1, likely toward the southeast. Density and velocity measurements demonstrated that the conditions near the depletion boundary were highly favorable to the gradient drift instability (GDI) with the one‐dimensional growth rate estimated to be ∼0.01 s−1. Since these conditions persisted for many hours, this growth rate was more than sufficient for the GDI to be considered the primary driver of irregularity formation in this case.

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Advanced separation and classification of ionospheric troughs in midnight conditions

Karpachev

2022

Sci Rep

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This study uses a novel approach to separate and classify different ionospheric troughs from CHAMP satellite data in the winter midnight ionosphere of the southern hemisphere at high solar activity (2000–2002). The main ionospheric trough (MIT) was separated from the high latitude trough (HLT). The separation was performed through an analysis of troughs in the frame of a model of the diffuse auroral particle precipitation. Two types of HLT were distinguished. In the mid-latitude ionosphere, the MIT was separated from the ring ionospheric trough (RIT), which is formed by the decay processes of the magnetospheric ring current. The separation was performed on the basis of an analysis of the prehistory of all geomagnetic disturbances for the period under study. In addition, a decrease in the electron density, which is superimposed on the MIT and masks its minimum position, is quite often observed at American and Atlantic longitudes near the Polar Circle.

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Discovery of a low-latitude ionospheric trough associated with the inner radiation belt

Cited by 3 publications

References 31 publications

Statistical Analysis of Ring Ionospheric Trough Characteristics

Statistical Analysis of Ring Ionospheric Trough Characteristics

Irregularities Observed at the Edge of a Mid‐Latitude Ionospheric Depletion Following a Geomagnetic Storm

Advanced separation and classification of ionospheric troughs in midnight conditions

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