Sudden phase anomalies (SPA's) observed in the phase of GBR 16 kHz VLF signals during the years 1977 to 1983 have been analysed in the light of their associated solar X-ray fluxes in the 0.5–4 Å and 1–8 Å bands. An attempt has been made to investigate the solar zenith angle (χ) dependence of the integrated solar X-ray flux for producing SPA's. It is deduced from the observations for χ < 81° that the phase deviation increases linearly as a whole with increasing solar X-ray fluxes in these two bands. The threshold X-ray flux needed to produce a detectable SPA effect has been estimated to be 1.6 × 10−4 ergcm−2 s−1 and 1.8 × 10−3 ergcm−2 s−1 in the 0.5–4 Å and 1–8 Å bands, respectively. For both bands the average cross section for all atmospheric constituents at a height of 70 km is almost equal to the absorption cross section for the 3 Å X-ray emission.
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Champion, K.S.W.: 1975,J. Atmos. Terr. Phys. 37, 915.
Chilton, C.J., Steele, F.K. and Norton, R.B.: 1963,J. Geophys. Res. 68, 5421.
Bracewell, R.N. and Straker, T.W.: 1949,Monthly Not. Roy. Astr. Soc. 109, 28.
Deshpande, S.D., Subrahmanyam, C.V. and Mitra, A.P.: 1972,J. Atmos. Terr. Phys. 34, 211.
Dubey, R.C., Gupta, S.K. and Pande, M.C.: 1977,Indian J. Rad. and Space Phys. 6, 67.
Friedman, H.: 1962 in: J.A. Ratcliff (ed.),Physics of the Upper Atmosphere, Academic Press, New York, p. 133.
Ijima, S., Terao, M. and Fujiwara, K.: 1968,Ann. Tokyo. Astron. Obs. 11, 1.
Gough, M.P.: 1974,J. Atmos. Terr. Phys. 34, 211.
Kaufmann, P. and Barros de Paes, M.H.: 1969,Solar Phys. 9, 478.
Kaufmann, P. and Mendes, A.: 1970,J. Atmos. Terr. Phys. 32, 427.
Kreplin, R.W. Chubb, T.A. and Friedman, H.: 1962,J. Geophys. Res. 67, 2231.
Mahra, H.S.: 1976,Proceedings of National Seminar on Time and Frequency, held at NPL, New Delhi, p. 121.
Mitra, A.P.: 1966, in: R.L. Smith-Rose (ed.),Space Research VI, p. 558.
Mitra, A.P.: 1974,Ionospheric Effects of Solar Flares, D. Reidel Publ. Co., Dordrecht.
Muraoka, Y. Murata, H. and Sato, T.: 1977,J. Atmos. Terr. Phys. 39, 787.
Nicolet, M. and Aiken, A.C.: 1960,J. Geophys. Res. 65, 1469.
Pant, P. and Mahra, H.S.: 1980,Indian J. Rad. and Space Phys. 9, 134.
Pant, P., Mahra, H.S. and Pande, M.C.: 1983,Indian J. Rad. and Space Phys. 12, 40.
Sato, T.: 1975,J. Geomag. Geoelectr. 27, 95.
Sengupta, P.R.: 1971,J. Atmos. Terr. Phys. 33, 1953.
Whitten, R.C. and Poppoff, I.G.: 1961,J. Geophys. Res. 66, 2779.
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Pant, P. Relation between VLF phase deviations and solar X-ray fluxes during solar flares. Astrophys Space Sci 209, 297–306 (1993). https://doi.org/10.1007/BF00627449
- Phase Deviation
- Solar Flare
- Zenith Angle
- Absorption Cross Section