Skip to main content
SpringerLink
Log in

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

  • Original Article
  • Published:
Astrophysics and Space Science Aims and scope Submit manuscript

Abstract

Excess solar X-ray radiation during solar flares causes an enhancement of ionization in the ionospheric D-region and hence affects sub-ionospherically propagating VLF signal amplitude and phase. VLF signal amplitude perturbation (ΔA) and amplitude time delay (Δt) (vis-á-vis corresponding X-ray light curve as measured by GOES-15) of NWC/19.8 kHz signal have been computed for solar flares which is detected by us during Jan–Sep 2011. The signal is recorded by SoftPAL facility of IERC/ICSP, Sitapur (22∘ 27′N, 87∘ 45′E), West Bengal, India. In first part of the work, using the well known LWPC technique, we simulated the flare induced excess lower ionospheric electron density by amplitude perturbation method. Unperturbed D-region electron density is also obtained from simulation and compared with IRI-model results. Using these simulation results and time delay as key parameters, we calculate the effective electron recombination coefficient (α eff ) at solar flare peak region. Our results match with the same obtained by other established models. In the second part, we dealt with the solar zenith angle effect on D-region during flares. We relate this VLF data with the solar X-ray data. We find that the peak of the VLF amplitude occurs later than the time of the X-ray peak for each flare. We investigate this so-called time delay (Δt). For the C-class flares we find that there is a direct correspondence between Δt of a solar flare and the average solar zenith angle Z over the signal propagation path at flare occurrence time. Now for deeper analysis, we compute the Δt for different local diurnal time slots DT. We find that while the time delay is anti-correlated with the flare peak energy flux ϕ max independent of these time slots, the goodness of fit, as measured by reduced-χ 2, actually worsens as the day progresses. The variation of the Z dependence of reduced-χ 2 seems to follow the variation of standard deviation of Z along the T x -R x propagation path. In other words, for the flares having almost constant Z over the path a tighter anti-correlation between Δt and ϕ max was observed.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15

Similar content being viewed by others

References

  • Ananthakrishnan, S., Abdu, M.A., Piazza, L.R.: D-region recombination coefficients and the short wavelengths X-ray flux during a solar flare. Planet. Space Sci. 21, 367–375 (1973)

    Article  ADS  Google Scholar 

  • Appleton, E.V.: A note on the sluggishness of the ionosphere. J. Atmos. Terr. Phys. 3, 282–284 (1953)

    Article  Google Scholar 

  • Balachandra Swamy, A.C.: A new technique for estimating D-region effective recombination coefficients under different solar flare conditions. Astrophys. Space Sci. 185, 153–164 (1991)

    Article  ADS  Google Scholar 

  • Basak, T., Chakrabarti, S.K., Pal, S.: Global effects on ionospheric weather over the Indian subcontinent at sunrise and sunset. AIP Conf. Proc. 1286, 137–149 (2010)

    Article  ADS  Google Scholar 

  • Chakrabarti, S.K., Mondal, S.K., Sasmal, S., Pal, S., Basak, T., Chakrabarti, S., Bhowmick, D., Ray, S., Maji, S.K., Nandi, A., Yadav, V.K., Kotoch, T.B., Khadha, B., Giri, K., Garain, S.K., Choudhury, A.K., Partra, N.N., Iqbal, N.: VLF signals in summer and winter in the Indian sub-continent using multi-station campaigns. Indian J. Phys. 86(5), 323–334 (2012)

    Article  ADS  Google Scholar 

  • del Pozo, C.F., Hargraves, J.K., Aylward, A.D.: Ion composition and effective ion recombination rate in the nighttime auroral lower ionosphere. J. Atmos. Sol.-Terr. Phys. 59(15), 1919–1943 (1997)

    Article  ADS  Google Scholar 

  • Fehsenfeld, F.C., Ferguson, E.E.: Origin of water cluster ions in the D region. J. Geophys. Res. 74, 2217–2222 (1969)

    Article  ADS  Google Scholar 

  • Ferguson, J.A.: Computer programs for assessment of long-wavelength radio communications, version 2.0. Technical document 3030, Space and Naval Warfare Systems Center, San Diego (1998)

  • Friedrich, M., Torkar, K.M., Steiner, R.J.: Empirical recombination rates in the lower ionosphere. Adv. Space Res. 34, 1937–1942 (2004)

    Article  ADS  Google Scholar 

  • Garcia-Rigo, A., Hernandez-Pajares, M., Juan, J.M., Sanz, J.: Solar flare detection system based on global positioning system data: first results. Adv. Space Res. 39, 889–895 (2007)

    Article  ADS  Google Scholar 

  • Gledhill, J.A.: The effective recombination coefficient of electrons in the ionosphere between 50 and 150 km. Radio Sci. 21(30), 399–408 (1986)

    Article  ADS  Google Scholar 

  • Grubor, D., Sulic, D., Zigman, V.: Influence of solar X-ray flares on the Earth-ionosphere waveguide. Serb. Astron. J. 171, 29–35 (2005)

    Article  ADS  Google Scholar 

  • Han, F., Cummer, S.A., Li, J., Lu, G.: Daytime ionospheric D region sharpness derived from VLF radio atmospheric. J. Geophys. Res. 116, A05314 (2011)

    Article  ADS  Google Scholar 

  • Kasturirangan, K., Rao, U.R., Sharma, D.P., Rastogi, R.G., Chakravarty, S.C.: Ionospheric effects of transient celestial X-ray and gamma-ray events. Astrophys. Space Sci. 42(1), 57–62 (1976)

    Article  ADS  Google Scholar 

  • Le, H., Liu, L., Chen, B., Lei, J., Yue, X., Wan, W.: Modeling the responses of the middle latitude ionosphere to solar flares. J. Atmos. Sol.-Terr. Phys. 69, 1587–1598 (2007)

    Article  ADS  Google Scholar 

  • Le, H., Liu, L., Chen, Y., Wan, W.: Statistical analysis of ionospheric responses to solar flares in the solar cycle 23. J. Geophys. Res. (2012). doi:10.1029/2012JA017934

    Google Scholar 

  • McRae, W.M., Thomson, N.R.: Solar flare induced ionospheric D-region enhancements from VLF phase and amplitude observations. J. Atmos. Sol.-Terr. Phys. 66, 77–87 (2004)

    Article  ADS  Google Scholar 

  • Mitra, A.P.: Recombination processes in the ionosphere. In: Advan. in Upper Atmos. Res., Ed. Landmark, pp. 57–87. Pergamon Press, Elmsford (1963)

    Google Scholar 

  • Mitra, A.P.: Ionospheric Effects of Solar Flares. Reidel, Dordrecht (1974)

    Book  Google Scholar 

  • Mitra, S.K.: The Upper Atmosphere. The Asiatic Society, Calcutta (1992)

    Google Scholar 

  • Mitra, A.P., Jones, R.E.: Recombination in the lower ionosphere. J. Geophys. Res. 50(3), 391–406 (1953)

    Google Scholar 

  • Mitra, A.P., Rowe, J.N.: Ionospheric effects of solar flares—VI. Changes in D-region ion chemistry during solar flares. J. Atmos. Terr. Phys. 34, 795–806 (1972)

    Article  ADS  Google Scholar 

  • Mitra, A.P., Rowe, J.N.: Ionospheric constraints of mesospheric nitric oxide. J. Atmos. Terr. Phys. 36, 1797–1808 (1974)

    Article  ADS  Google Scholar 

  • Nina, A., Cadez, V., Sulic, D., Sreckovic, V., Zigman, V.: Effective electron recombination coefficient in ionospheric D-region during the relaxation regime after solar flare from February 18, 2011. Nucl. Instrum. Methods Phys. Res. B 279, 106–109 (2011)

    Article  ADS  Google Scholar 

  • Osepian, A., Kirkwood, S., Dalin, P., Tereschenko, V.: D-region electron density and effective recombination coefficients during twilight-experimental data and modelling during solar proton events. Ann. Geophys. 27, 3713–3724 (2009)

    Article  ADS  Google Scholar 

  • Pal, S., Chakrabarti, S.K.: Theoretical models for computing VLF wave amplitude and phase and their applications. AIP Conf. Proc. 1286, 42–60 (2010)

    Article  ADS  Google Scholar 

  • Pal, S., Chakrabarti, S.K., Mondal, S.K.: Modeling of sub-ionospheric VLF signal perturbations associated with total solar eclipse, 2009 in Indian subcontinent. Adv. Space Res. 50(2), 196–204 (2012a)

    Article  ADS  Google Scholar 

  • Pal, S., Maji, S.K., Chakrabarti, S.K.: First ever VLF monitoring of the lunar occultation of a solar flare during the 2010 annular solar eclipse and its effects on the D-region electron density profile. Planet. Space Sci. 73, 310–317 (2012b)

    Article  ADS  Google Scholar 

  • Pant, P.: Relation between VLF phase deviations and solar X-ray fluxes during solar flares. Astrophys. Space Sci. 209, 297–306 (1993)

    Article  ADS  Google Scholar 

  • Parthasarathy, R., Rai, D.B.: Effective recombination coefficient in D-region. Scientific Report No. 1, Geophy. Inst. of the Univ. of Alaska (1965)

  • Poppoff, I.G., Whitten, R.C.: D-region ionization by solar X-rays. J. Geophys. Res. 67(7), 2986–2988 (1962)

    Article  ADS  Google Scholar 

  • Qian, L., Burns, A.G., Chamberlin, P.C., Solomon, S.C.: Variability of thermosphere and ionosphere responses to solar flares. J. Geophys. Res. 116, AI0309 (2011)

    Article  Google Scholar 

  • Rowe, J.N., Ferraro, A.J., Lee, H.S., Kreplin, R.W., Mitra, A.P.: Observations of electron density during a solar flare. J. Atmos. Terr. Phys. 32, 1609–1614 (1970)

    Article  ADS  Google Scholar 

  • Schmitter, E.D.: Remote sensing planetary waves in the mid-latitude mesosphere using low frequency transmitter signals. Ann. Geophys. 29, 1287–1293 (2011)

    Article  ADS  Google Scholar 

  • Sharma, D.P., Jain, A.K., Chakravarty, S.C., Kasturirangan, K., Ramanathan, K.R., Rao, U.R.: Possibility of continuous monitoring of celestial X-ray sources through their ionization effects in the nocturnal D-region ionosphere. Astrophys. Space Sci. 17(2), 409–425 (1972)

    Article  ADS  Google Scholar 

  • Sharma, D.K., Rai, J., Israil, M., Subrahmanyam, P., Chopra, P., Garg, S.C.: Enhancement in electron and ion temperatures due to solar flares by SROSS-C2 satellite. Ann. Geophys. 22, 2047–2052 (2004)

    Article  ADS  Google Scholar 

  • Thomson, N.R., Clilverd, M.A.: Solar flare induced ionospheric D-region enhancements from VLF amplitude observations. J. Atmos. Terr. Phys. 63, 1729–1737 (2001)

    Article  ADS  Google Scholar 

  • Thomson, N.R., Rodger, C.J., Clilverd, M.A.: Large solar flares and their ionospheric D region enhancements. J. Geophys. Res. 110, A06306 (2005)

    Article  ADS  Google Scholar 

  • Tsurutani, B.T., Verkhoglyadova, O.P., Mannucci, A.J., Lakhina, G.S., Li, G., Zank, G.P.: A brief review of “solar flare effects” on the ionosphere. Radio Sci. 44, RSOA17 (2009)

    Article  Google Scholar 

  • Valnicek, B., Ranzinger, P.: X-ray emission and D-region ‘sluggishness’. Bull. Astron. Inst. Czechoslov. 23, 318–322 (1972)

    ADS  Google Scholar 

  • Wagner, L.S., Thome, G.D.: Measurement of E-layer effective recombination coefficient during solar flares. Radio Sci. 7(4), 469–480 (1972)

    Article  ADS  Google Scholar 

  • Wait, J.R.: Electromagnetic Waves in Stratified Media. Pergamon Press, Oxford (1962)

    MATH  Google Scholar 

  • Wait, J.R., Spies, K.P.: Characteristics of the Earth-ionosphere waveguide for VLF radio waves. NBS Tech. Note 300 (1964)

  • Whitten, R.C., Poppoff, I.G.: A model of solar-flare-induced ionization in the D region. J. Geophys. Res. 66(9), 2779–2786 (1961)

    Article  ADS  Google Scholar 

  • Whitten, R.C., Poppoff, I.G.: Associative detachment in the D region. J. Geophys. Res. 67(3), 1183–1185 (1962)

    Article  ADS  Google Scholar 

  • Whitten, R.C., Poppoff, I.G., Edmonds, R.S., Berning, W.W.: Effective recombination coefficients in the lower ionosphere. J. Geophys. Res. 70(7), 1737–1742 (1965)

    Article  ADS  Google Scholar 

  • Zhang, D.H., Mo, X.H., Cai, L., Zhang, W., Feng, M., Hao, Y.Q., Xiao, Z.: Impact factor for the ionosphere total electron content response to solar flare irradiation. J. Geophys. Res. 116, A04311 (2011)

    Article  ADS  Google Scholar 

  • Zigman, V., Grubor, D., Sulic, D.: D-region electron density evaluated from VLF amplitude time delay during X-ray solar flares. J. Atmos. Terr. Phys. 69, 775–792 (2007)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

We thank S. Pal and S.K. Mondal for discussions and ICSP for allowing us to use the IERC data. Tamal Basak acknowledges a CSIR Fellowship for support.

Author information

Authors and Affiliations

  1. S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata, 700098, India

    Tamal Basak & Sandip K. Chakrabarti

  2. Indian Centre for Space Physics, 43 Chalantika, Garia Station Road, Garia, Kolkata, 700084, India

    Sandip K. Chakrabarti

Authors
  1. Tamal Basak
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Sandip K. Chakrabarti
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Tamal Basak.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Basak, T., Chakrabarti, S.K. 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. Astrophys Space Sci 348, 315–326 (2013). https://doi.org/10.1007/s10509-013-1597-9

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10509-013-1597-9

Keywords

Search

Navigation