Magnetic storms and their effects in the lower ionosphere: Differences in storms of various types

Соколов, С. Н.

doi:10.1134/s0016793211050124

Cited by 16 publications

(7 citation statements)

References 47 publications

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“…This excess change in electron density could play a significant role during sunrise transition period and continues up to the late morning [ King and Fooks , ]. Sokolov [] discussed that the observed differences in the effects of storms in the D region are related to the differences in the corresponding types of storms determined by the observed fluxes of energetic electrons. Table presents brief results of some of the percentage deviations in electron density due to geomagnetic storms.…”

Section: Discussionmentioning

confidence: 99%

“…Fluctuations in the VLF/LF signal during such a storm are an indication of varying disturbances of the D region ionosphere along the GCP. Sokolov [] discussed that the differences in manifestations of storms in the lower ionosphere are mainly caused by the time and spatial differences in precipitations of energetic electrons. As the magnetosphere fills up with a major influx of relativistic particles from the solar wind, these relativistic particles starts to precipitate at the D region of the ionosphere.…”

Section: Discussionmentioning

confidence: 99%

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Long‐duration geomagnetic storm effects on the D region of the ionosphere: Some case studies using VLF signal

Choudhury

Guha

et al. 2015

JGR Space Physics

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The present work investigates the effects of long-duration geomagnetic storms on VLF signal during ionospheric sunrise time, commonly known as D Layer Preparation Time (DLPT) depth. The VLF signal at 19.8 kHz transmitted from Northwest Cape, Australia, and received at a low-latitude station, Tripura, India, is used for the present analysis. The data for the analysis are selected from November 2008 to October 2011. In the active period of the geomagnetic storms, the average DLPT depth is found to have a negative correlation coefficient of 0.91 with geomagnetic Ap index. It is also found that with each 10 unit increase of Ap index, the DLPT depth (the day and night asymmetry level) changes by 1.25 dB. The results are supported with modeled International Reference Ionosphere (IRI) electron density data and DLPT depth at 71 km height for the three positions, namely, receiver position, signal hop position, and the transmitter position along the total Great Circle Path. It is found that the receiver position electron density is the main controlling factor for DLPT depth. The correlation between IRI electron density and DLPT depth increases from À0.13 at transmitter position to À0.33 at the first hop position, to À0.46 at the receiver position, respectively. The percentage change of post storm electron density, at 71 km height, is found to increase by more than 100% at the receiver position. The results are discussed on the basis of the electron density changes over the signal propagation path, mainly caused by the geomagnetic storms.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Long‐duration geomagnetic storm effects on the D region of the ionosphere: Some case studies using VLF signal

Choudhury

Guha

et al. 2015

JGR Space Physics

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“…Based on the analysis of phase measurements of the Omega VLF signal, the detailed investigation of the poststorm effect in mid-latitude paths has been reported by Sokolov (2011). The author has shown that anomalies in phase were observed in four paths up to 11-12 days during and after magnetic storms.…”

Section: Discussionmentioning

confidence: 99%

“…Previously, VLF phase and amplitude variations and their relationship with geomagnetic activity at mid-latitudes have been studied in the region 10.2-13.6 kHz of the global navigation system "Omega" (see, e.g., Belrose and Thomas, 1968;Potemra and Rosenberg, 1973;Kikuchi, 1981;Sokolov, 2011). In general, the phase disturbances were registered during magnetic storms and the days following the recovery of the geomagnetic field.…”

Section: Introductionmentioning

confidence: 99%

Correlation of very low and low frequency signal variations at mid-latitudes with magnetic activity and outer-zone particles

et al. 2014

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Abstract. The disturbances of very low and low frequency signals in the lower mid-latitude ionosphere caused by magnetic storms, proton bursts and relativistic electron fluxes are investigated on the basis of VLF-LF measurements obtained in the Far East and European networks. We have found that magnetic storm (−150 < Dst < −100 nT) influence is not strong on variations of VLF-LF signals. The anomalies with negative amplitude were registered during the main and recovery phases for several magnetic storms (mainly for three northernmost paths). The correlation between VLF-LF signals and geomagnetic activity is rather weak even for these paths (≈ 12-18 %). Also, the correlation between magnetic activity and VLF signal variations recorded onboard the DEMETER satellite is not found. The significant influence of outer-zone particles (energetic particle sensor on board/Geostationary Operational Environmental Satellite (GOES) measurements) on the VLF-LF signal variations is found for almost half of the sub-ionospheric paths.

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“…The main problem in applying this method for earthquake prediction is distinguishing the signal anomalies of seismic origin against the background of global perturbations, which are caused in the lower ionosphere by magnetic storms and sub-storms, and proton and electron fluxes. It was previously established that magnetic storms and solar energetic particle fluxes can induce phase and amplitude variations in the VLF signal [ 6 , 7 , 8 , 9 ]. The correlation of the phase and amplitude variations in the LF signal to the disturbance storm time (DST) index, as well as the correlation of the outer-zone particles (protons and electrons) to the high-pitch angle was revealed in [ 10 , 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

The Behavior of VLF/LF Variations Associated with Geomagnetic Activity, Earthquakes, and the Quiet Condition Using a Neural Network Approach

Попова

Рожной

Solovieva

et al. 2018

Entropy

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The neural network approach is proposed for studying very-low- and low-frequency (VLF and LF) subionospheric radio wave variations in the time vicinities of magnetic storms and earthquakes, with the purpose of recognizing anomalies of different types. We also examined the days with quiet geomagnetic conditions in the absence of seismic activity, in order to distinguish between the disturbed signals and the quiet ones. To this end, we trained the neural network (NN) on the examples of the representative database. The database included both the VLF/LF data that was measured during four-year monitoring at the station in Petropavlovsk-Kamchatsky, and the parameters of seismicity in the Kuril-Kamchatka and Japan regions. It was shown that the neural network can distinguish between the disturbed and undisturbed signals. Furthermore, the prognostic behavior of the VLF/LF variations indicative of magnetic and seismic activity has a different appearance in the time vicinity of the earthquakes and magnetic storms.

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Magnetic storms and their effects in the lower ionosphere: Differences in storms of various types

Cited by 16 publications

References 47 publications

Long‐duration geomagnetic storm effects on the D region of the ionosphere: Some case studies using VLF signal

Long‐duration geomagnetic storm effects on the D region of the ionosphere: Some case studies using VLF signal

Correlation of very low and low frequency signal variations at mid-latitudes with magnetic activity and outer-zone particles

The Behavior of VLF/LF Variations Associated with Geomagnetic Activity, Earthquakes, and the Quiet Condition Using a Neural Network Approach

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