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In 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 (VLF/LF) radio waves and it is related to the considered area and time period. The obtained expressions are applied to data for the VLF signal emitted in Germany and recorded in Serbia during the solar X-ray flare detected by the GOES-14 satellite on May 5, 2010.
PAPER REVISED: 2019-06-01
PAPER ACCEPTED: 2019-07-11
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  1. Singh, A.K., et al., Solar Flare Induced D-region Ionospheric Perturbations Evaluated from VLF Measurements. Astrophysics and Space Science, 350 (2014), pp. 1:1-9
  2. Srećković, V.A., et al., The Effects of Solar Activity: Electrons in the Terrestrial Lower Ionosphere. Journal of the Geographical Institute "Jovan Cvijic" SASA, 67(2017), 3, pp. 221-233
  3. Todorović Drakul, M., et al., Behaviour of Electron Content in the Ionospheric D-region During Solar X-ray Flares. Serbian Astronomical Journal, 193 (2016), pp. 11-18
  4. Nina, A., et al., Diagnostics of Plasma in the Ionospheric D-region: Detection and Study of Different Ionospheric Disturbance Types. European Physical Journal D, 71 (2017), 7, pp. 189: 1-12
  5. Nina, A., et al., Analysis of the Relationship Between the Solar X-ray Radiation Intensity and the D-region Electron Density Using Satellite and Ground-based Radio Data. Solar Physics, 293 (2018), pp. 64: 1-19
  6. Uigman, V., et al., D-region Electron Density Evaluated from VLF Amplitude Time Delay During X-ray Solar Flares. Journal of Atmospheric and Solar-Terrestrial Physics, 69 (2007), pp. 775-792
  7. Nina, A., Čadež, V.M., Electron Production by Solar Ly-α Line Radiation in the Ionospheric D-region. Advances in Space Research, 54 (2014), 7, pp. 1276-1284
  8. Bajčetić, J., et al., Ionospheric D-region Temperature Relaxation and its Influences on Radio Signal Propagation after Solar X-flares Occurrence. Thermal Science, 19 (2015), Suppl.2, pp. S299-S309
  9. Thomson, N.R. et al., Large Solar Flares and their Ionospheric D Region Enhancements. Journal of Geophysical Research (Space Physics), 110 (2015), pp. A06306: 1-10
  10. Ferguson, J.A., Computer Programs for Assessment of Long-Wavelength Radio Communications, Version 2.0, Space and Naval Warfare Systems Center, San Diego, USA, 1998
  11. Woods, T.N., et al., et al., New Solar Extreme-ultraviolet Irradiance Observations, The Astrophysical Journal, 739 (2011), 2, pp. 59: 1-13
  12. Cohen, M.B., et al., Sensitive Broadband ELF/VLF Radio Reception With the AWESOME Instrument. IEEE Transactions on Geoscience and Remote Sensing, 48:3-17, January 2010.
  13. Radovanović. M, Investigation of Solar Influence on the Terrestrial Processes: Activities in Serbia. Journal of the Geographical Institute "Jovan Cvijic" SASA, 68 (2018), 1, pp. 149 - 155
  14. Wait, J.R., Spies, K.P., Characteristics of the Earth-ionosphere Waveguide for VLF Radio Waves, NBS Technical Note, CO, USA, 1964
  15. Thomson, N.R, Experimental Daytime VLF Ionospheric Parameters. Journal of Atmospheric and Terrestrial Physics, 55 (1993), pp. 173-184
  16. Grubor, D.P., et al., Classification of X-ray Solar Flares Regarding their Effects on the Lower Ionosphere Electron Density Profile. Annales Geophysicae, 26 (2008), pp. 1731-1740
  17. Kumar, S., et al., Perturbations to the Lower Ionosphere by Tropical Cyclone Evan in the South Pacific Region. Journal of Geophysical Research: Space Physics, 122 (2017), pp. 8720-8732
  18. Nina,A., et al., Altitude Distribution of Electron Concentration in Ionospheric D-region in Presence of Time-varying Solar Radiation Flux. Nuclear Instruments and Methods in Physics Research B, 279 (2012), pp. 110-113
  19. Kolarski, A., Davorka Grubor, D., Sensing the Earth's Low Ionosphere During Solar Flares Using VLF Signals and GOES Solar X-ray Data. Advances in Space Research, 53 (2014), 11, pp. 1595 - 1602
  20. McEwan M., Phillips, F., Chemistry of the Atmosphere, Mir, Moscow, Russia, 1978
  21. Blaunstein N., Christodoulou, C., Radio Propagation and Adaptive Antennas for Wireless Communication Links: Terrestrial, Atmospheric and Ionospheric, John Wiley and Sons, Inc., Hoboken, New Jersey, 2006
  22. Deshpande S.D., Mitra, A.P., Ionospheric Effects of Solar Flares - III. the Quantitative Relationship of Flare X-rays to SID's. Journal of Atmospheric and Terrestrial Physics, 34 (1972), 2, pp. 243 - 253
  23. Hayes, L.A., et al., Pulsations in the Earth's Lower Ionosphere Synchronized with Solar Flare Emission. Journal of Geophysical Research: Space Physics, 122 (2017), 10, pp. 9841-9847
  24. Mitra, A.P., Ionospheric Effects of Solar Flares, Mir, Moscow, Russia, 1974
  25. Sato, T., The Response of the Lower Ionosphere to the Great Solar Flare of August 7, 1972. Journal of Geomagnetism and Geoelectricity, 27 (1975), 5, pp. 383-407
  26. Osepian, A., et al., D-region Electron Density and Effective Recombination Coefficients During Twilight - Experimental Data and Modelling During Solar Proton Events. Annales Geophysicae, 27:3713-3724, October 2009.
  27. 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. Astrophysics and Space Science, 348 (2013), 2, pp. 315-326
  28. Rowe, J.N., Model Studies of the Lower Ionosphere, Sci. Rep.No. 406, Pennsylvania State Univ., Univ. Park, USA, 1972, 1972.
  29. Aikin, A.C., et al., Some Results of Rocket Experiments in the Quiet D Region. Journal of Geophysical Research, 69 (1964), pp. 4621-4628
  30. Bourdeau, R.E., et al., The Lower Ionosphere at Solar Minimum, Greenbelt, Md.: NASA, Goddard Space Flight Center. 1965.

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