Effective recombination coefficient and solar zenith angle effects on low-latitude D-region ionosphere evaluated from VLF signal amplitude and its time delay during X-ray solar flares

Basak, Tamal; Chakrabarti, Sandip K.

doi:10.1007/s10509-013-1597-9

Cited by 52 publications

(51 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In fig. 4 we show the relevant data for 74.1 km and 74 km obtained by fitting of dependencies α eff in the maximum X-radiation flux presented in [6,27] (fill and open scatters, respectively). In addition, in these studies we give calculated values for events of class very similar to the X-ray flare which we analyze.…”

Section: Resultsmentioning

confidence: 99%

Variations in ionospheric D-region recombination properties during increase of its X-ray heating induced by solar X-ray flare

et al. 2019

View full text Add to dashboard Cite

Original scientific paper https://doi.org/10.2298/TSCI190501313NIn this paper we present an analysis of parameters describing the effective recombination processes in the upper ionospheric D-region in the period of its additional heating by the X-radiation emitted during a solar X-ray flare. We present a procedure for calculation of the effective recombination coefficient and electron loss rate in the period when the X-radiation flux detected by the GOES satellite in the wavelength domain between 0.1 and 0.8 nm increases. The developed procedure is based on observational data obtained in the low ionospheric monitoring by the very low/low frequency radio waves and it is related to the considered area and time period. The obtained expressions are applied to data for the very low frequency signal emitted in Germany and recorded in Serbia during the solar X-ray flare detected by the GOES-14 satellite on May 5, 2010.

show abstract

Section: Resultsmentioning

confidence: 99%

Variations in ionospheric D-region recombination properties during increase of its X-ray heating induced by solar X-ray flare

et al. 2019

View full text Add to dashboard Cite

show abstract

“…In our results we observe that peak of the electron density and the peak of the ionization rate occur at different times. As discussed in numerous papers (Zigman et al, 2007;Basak et al, 2013;Palit et al, 2014), the electron density peak and hence VLF modulation peak during any such ionization event should appear after a delay from that of the event peak or the ionization peak. This is due to the sluggishness of the lower ionosphere.…”

Section: Observation and Analysismentioning

confidence: 94%

Inverse problem in ionospheric science: prediction of solar soft-X-ray spectrum from very low frequency radiosonde results

Palit

Ray

Chakrabarti

2016

Astrophys Space Sci

View full text Add to dashboard Cite

X-rays and gamma-rays from astronomical sources such as solar flares are mostly absorbed by the Earth's atmosphere. Resulting electron-ion production rate as a function of height depends on the intensity and wavelength of the injected spectrum and therefore the effects vary from one source to another. In other words, the ion density vs. altitude profile has the imprint of the incident photon spectrum. In this paper, we investigate whether we can invert the problem uniquely by deconvolution of the VLF amplitude signal to obtain the details of the injected spectrum. We find that it is possible to do this up to a certain accuracy. Our method is useful to carry out a similar exercise to infer the spectra of more energetic events such as the Gamma Ray Bursts (GRBs), Soft Gamma Ray Repeaters (SGRs) etc. by probing even the lower part of the atmosphere. We thus show that to certain extent, the Earth's atmosphere could be used as a gigantic detector of relatively strong events.

show abstract

“…This is one of the major assumptions for the numerical modelling as used by various scientist such as Hayakawa et al (1996), , Clilverd et al (1999), Rodger et al (1999). Also in numerical modelling, this assumption was used in a vast scale by Budden (1961), Baba et al (1998), Wait and Spices (1964), Pal et al (2012), Basak and Chakrabarti (2013), Palit et al (2013). It is obvious that the decrease in the reflection height modified the total path length of the radio wave and this changes the phase of the VLF signal.…”

Section: Introductionmentioning

confidence: 99%

Studies of seismo-ionospheric correlations using anomalies in phase of very low frequency signal

Pal

Sasmal

Chakrabarti

2017

Geomatics, Natural Hazards and Risk

View full text Add to dashboard Cite

We present the results of the statistical analysis of very low frequency (VLF) signal transmitted from NWC transmitter (latitude 21.8 S, longitude 114.15 E) at 19.8 kHz received at Ionospheric and Earthquake Research Centre (IERC) (latitude 22.50 N, longitude 87.79 E). We analyse the phase of VLF signal for the whole year 2011 and compute the sunrise and sunset terminator time from it. We observe unusual shift of these sunrise and sunset terminator time during seismic events for which the earthquake epicentres are in India and its subcontinent region. We calculate the total energy accumulation by all those earthquakes for a single day and compute the effective magnitude of all the earthquakes for that day which behaves as a single quake. We compute a cross correlation between fluctuation in terminator time shifts from the normal value with effective magnitude of earthquake. We found that the unusual fluctuations in terminator time are well correlated with earthquake magnitude and the fluctuation is maximum on two days prior to earthquake events.

show abstract

Effective recombination coefficient and solar zenith angle effects on low-latitude D-region ionosphere evaluated from VLF signal amplitude and its time delay during X-ray solar flares

Cited by 52 publications

References 46 publications

Variations in ionospheric D-region recombination properties during increase of its X-ray heating induced by solar X-ray flare

Variations in ionospheric D-region recombination properties during increase of its X-ray heating induced by solar X-ray flare

Inverse problem in ionospheric science: prediction of solar soft-X-ray spectrum from very low frequency radiosonde results

Studies of seismo-ionospheric correlations using anomalies in phase of very low frequency signal

Contact Info

Product

Resources

About