Skip to main content

Equatorial electrojet studies from rocket and ground measurements

Abstract

Combining the data of in-situ measurements of ionospheric current, Jm by rocket-borne instruments and the ground based geomagnetic H field close to the magnetic equator a linear relation has been found between the peak current density Jm and the daily range of H, (RH). This relationship has been used to convert long series of RH data into Jm. Combining Jm and the E-region peak electron density Nm, the electron velocity in the ionosphere, VE has been calculated. It is shown that after all corrections are made of the solar zenith angle variations, the ionospheric current as well as electron drift in American and Indian sectors show strong equinoctial maxima, the mean values of both the parameters are larger at American than in Indian sector. The solar cycle variation of the electrojet current is primarily due to the variations of NmE, and not due to the variations of electric field. The diurnal variation of the electric field with peak at 09–10 LT interacting with noon peak of NmE making ΔH to peak at an hour earlier than noon. It is stressed to realise the importance of electric field in diurnal, seasonal and longitudinal variations of the equatorial electrojet current.

References

  • Broun, J. A., Trivandrum magnetic observations Vol. I, 576 pp., Henry S. King and Co., London, 1874.

    Google Scholar 

  • Cain, J. C. and R. E. Sweeney, The POGO data, J. Atmos. Terr. Phys., 35, 1271–1247, 1973.

    Google Scholar 

  • Chandra, H. and R. G. Rastogi, Daily variation of F-region drifts at Thumba, J. Atmos. Terr. Phys., 32, 1309–1311, 1970.

    Article  Google Scholar 

  • Chandra, H., R. K. Misra, and R. G. Rastogi, Equatorial ionospheric drift and the electrojet, Planet. Space Sci., 19, 1497–1503, 1971.

    Article  Google Scholar 

  • Chapman, S., The equatorial electrojet as detected from the abnormal electric current distribution above Huancayo, Peru and elsewhere, Arch. Meteorol. Geophys. Bioclimatal, A4, 368–390, 1951.

    Article  Google Scholar 

  • Chapman, S. and K. S. Rajarao, The H and Z variations along and near the equatorial electrojet in India, Africa and the Pacific, J. Atmos. Terr. Phys., 27, 559–581, 1965.

    Article  Google Scholar 

  • Davies, T. N, K. Burrows, and J. D. Stolarik, A latitude survey of the equatorial electrojet with rocket-borne magnetometers, J. Geophys. Res., 72, 1845–1861, 1967.

    Article  Google Scholar 

  • Deshpande, M. R. and R. G. Rastogi, Ionospheric horizontal drifts within the equatorial electrojet region in India, Ann. Geophys., 22, 418–421, 1966.

    Google Scholar 

  • Egedal, J., The magnetic diurnal variation of the horizontal force near the magnetic equator, Terr. Magn. Atmos. Electr., 52, 449–451, 1947.

    Article  Google Scholar 

  • Fejer, B. G., D. T. Farley, R. F. Woodman, and C. Calderon, Dependence of the equatorial F-region vertical drifts on season and solar cycle, J. Geophys. Res., 84, 5792–5796, 1979.

    Article  Google Scholar 

  • James, M. E., D. Tripathi, and R. G. Rastogi, Day to day variability of ionospheric current system, Ind. J. Radio & Space Phys., 25, 36–43, 1996.

    Google Scholar 

  • James, M. E., R. G. Rastogi, and D. R. K. Rao, Identification of the current system associated with a partially reversed equatorial electrojet, J. Geomag. Geoelectr., 49, 633–640, 1997.

    Article  Google Scholar 

  • Kane, R. P., Relationship between H ranges at equatorial and middle latitudes, J. Atmos. Terr. Phys., 33, 319–327, 1971.

    Article  Google Scholar 

  • Maynard, N. C., Measurements of ionospheric currents off the coast of Peru, J. Geophys. Res., 72, 1863–1875, 1967.

    Article  Google Scholar 

  • Maynard, N. C. and L. J. Cahill, Measurement of the equatorial electrojet over India, J. Geophys. Res., 70, 5923–5936, 1965.

    Article  Google Scholar 

  • Misra, R. K., H. Chandra, and R. G. Rastogi, Solar cycle effects in the electron drifts over the magnetic equator, J. Geomag. Geoelectr., 23, 181–186, 1971.

    Article  Google Scholar 

  • Mitra, S. N., A radio method of measuring winds in the ionosphere, Proc. IEEE, 96, 441–446, 1949.

    Google Scholar 

  • Onwumechilli, C. A. and C. E. Agu, Longitudinal variation of equatorial electrojet parameters derived from POGO satellite observations, Planet. Space Sci., 29, 627–634, 1981.

    Article  Google Scholar 

  • Onwumechilli, C. A., A. K. Kawasaki, and S.-I. Akasofu, Relationship between the equatorial electrojet and the polar magnetic variations, Planet. Space Sci., 21, 1–16, 1973.

    Article  Google Scholar 

  • Osborne, D. G., Correlations between quiet-day magnetic ranges, J. Atmos. Terr. Phys., 28, 45–51, 1966.

    Article  Google Scholar 

  • Patel, V. P. and R. G. Rastogi, On the solar control of the quiet day geomagnetic variations near the magnetic equator, Curr. Sci., 47, 325–327, 1978.

    Google Scholar 

  • Prakash, S., B. H. Subbaraya, and S. P. Gupta, Rocket measurements of ionization Irregularities in the equatorial ionosphere at Thumba and identification of plasma Instabilities, Ind. J. of Radio & Space Phys., 1, 72–80, 1972.

    Google Scholar 

  • Rastogi, R. G., A study of the noon critical frequencies of the E and F1 layers of the ionosphere, Geofisica Pura Appl. (Milano), 40, 145–156, 1958.

    Article  Google Scholar 

  • Rastogi, R. G., Enhancement of the lunar tide in the noon critical frequency of the F2 Layer over the magnetic equator, J. Res. (NBS), 66D, 601–606, 1962a.

    Google Scholar 

  • Rastogi, R. G., Longitudinal variation in the equatorial electrojet, J. Atmos. Terr. Phys., 24, 1031–1040, 1962b.

    Article  Google Scholar 

  • Rastogi, R. G., Lunar tidal oscillations in the solar daily range of H at equatorial stations during IGY-IGC, J. Geophys. Res., 69, 1020–1024, 1964.

    Article  Google Scholar 

  • Rastogi, R. G., Geomagnetic field variations at low latitudes and ionospheric electric field, J. Atmos. Terr. Phys., 55, 1375–1381, 1993.

    Article  Google Scholar 

  • Rastogi, R. G. and K. N. Iyer, Quiet day variation of geomagnetic H field at low latitudes, J. Geomag. Geoelectr., 28, 461–478, 1976.

    Article  Google Scholar 

  • Rastogi, R. G., H. Chandra, and S. C. Chakravarty, The disappearance of equatorial Es and the reversal of electrojet current, Proc. Ind. Acad. Sci., 74, 62–67, 1971.

    Google Scholar 

  • Rastogi, R. G., S. Alex, and A. Patil, Seasonal variation of geomagnetic D, H and Z fields at low latitudes, J. Geomag. Geoelectr., 46, 115–126, 1994.

    Article  Google Scholar 

  • Rastogi, R. G., M. E. James, and D. Tripathi, Longitudinal inequalities in equatorial ionospheric electric field, Ind. J. Radio & Space Phys., 25, 27–35, 1996a.

    Google Scholar 

  • Rastogi, R. G., H. Chandra, and M. E. James, Nocturnal variations of geomagnetic horizontal field at equatorial stations, Geophys. Res. Lett., 23, 2601–2604, 1996b.

    Article  Google Scholar 

  • Richmond, A. D., Modeling the ionosphere wind dynamo: A review, PAGEOPH, 131, 413–435, 1989.

    Article  Google Scholar 

  • Sampath, S. and T. S. G. Sastry, Results from in-situ measurements of ionospheric currents in the equatorial region—I, J. Geomag. Geoelectr., 31, 373–379, 1979a.

    Article  Google Scholar 

  • Sampath, S. and T. S. G. Sastry, Depth of non conducting layer in the Indian ocean region around Thumba, derived from in situ investigations of equatorial electrojet—II, J. Geomag. Geoelectr., 31, 381–389, 1979b.

    Article  Google Scholar 

  • Sastry, T. S. G., Quiet day electrojet over Thumba, India, J. Geophys. Res., 73, 1789–1794, 1968.

    Article  Google Scholar 

  • Schlapp, D. M., World-wide morphology of day-to-day variability of Sq, J. Atmos. Terr. Phys., 30, 1761–1776, 1968.

    Article  Google Scholar 

  • Schuman, B. M., Rocket measurement of the equatorial electrojet, J. Geophys. Res., 75, 3889–3901, 1970.

    Article  Google Scholar 

  • Sinha, H. S. S., H. Chandra, and R. G. Rastogi, Longitudinal inequalities in the equatorial electrojet, Proc. Nat. Acad. Sci., India, 69(A), I, 89–96, 1999.

    Google Scholar 

  • Somayajulu, V. V., Behaviour of harmonic components of the geomagnetic field during counter electrojet events, J. Geomag. Geoelectr., 40, 111–130, 1988.

    Article  Google Scholar 

  • Subbaraya, B. H., S. Prakash, and S. P. Gupta, Electron densities in the equatorial lower ionosphere from the Langmuir probe experiments conducted at Thumba during the years 1966–1978, Scientific Report ISRO-PRL-SR-15-83, 1983.

  • Takeda, M., Y. Yamada, and T. Araki, Simulation of ionospheric currents and geomagnetic field variations of Sq for different solar activity, J. Atmos. Terr. Phys., 48, 277–287, 1986.

    Article  Google Scholar 

  • Vikramkumar, B. T., K. S. Viswanathan, and P. B. Rao, VHF backscatter radar observations of the equatorial electrojet irregularities, Ann. Geophys., 2, 495–500, 1984.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to H. Chandra.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Chandra, H., Sinha, H.S.S. & Rastogi, R.G. Equatorial electrojet studies from rocket and ground measurements. Earth Planet Sp 52, 111–120 (2000). https://doi.org/10.1186/BF03351619

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1186/BF03351619

Keywords

  • Magnetic Equator
  • Ground Measurement
  • Ionospheric Current
  • Equatorial Electrojet
  • Solar Cycle Variation