Skip to main content
Earth, Planets and Space
Earth, Planets and Space Cover Image
Download PDF

Daytime ionospheric absorption features in the polar cap associated with poleward drifting F-region plasma patches

Earth, Planets and Space volume 50, pages107–117(1998)Cite this article

Abstract

Absorption of radio waves in the polar ionosphere near the magnetic noon was observed on October 8, 1991, by the 30 MHz imaging riometer at Ny-Alesund, Svalbard (invariant latitude 76.1°). These observations showed that the initially widespread absorption features became localized and enhanced in the high-latitude sector of the field of view, and followed a poleward motion. This behavior occurred quasi-periodically and repeated every 10–20 min. Simultaneous observations by EISCAT “Polar” experiments showed that nine discrete plasma patches, with F-region electron density enhanced by an order of 106 el/cm3, drifted poleward from the polar cusp to the cap during the same period. This coincidence suggested that the ionospheric absorption was associated with F-region plasma patches in the polar cap. Theoretical absorption values of 0.14 dB, estimated using the electron densities and the electron-ion collision frequencies from the EISCAT F-region plasma data, are smaller than the observed values (<0.8 dB). This discrepancy may be related to the difference between the theoretically- and experimentally-determined collision frequencies, as indicated by Wang et al. (1994). These localized, enhanced, and poleward drifting absorption features over Ny-Alesund may be explained as F-region plasma patches produced by a magnetosheath-like particle precipitation into the cusp, and as small-scale irregularities caused by density gradients of the patches drifting into the polar cap.

References

  1. Aggarwal, K. M., Narinder Nath, and C. S. K. Setty, Collision frequency and transport properties of electrons in the ionosphere, Planet. Space Sci., 27, 753–768, 1979.

    Article  Google Scholar 

  2. Anderson, D. N., J. Buchau, and R. A. Heelis, Origin of density enhancements in the winter polar cap ionosphere, Radio Sci., 23, 513–519, 1988.

    Article  Google Scholar 

  3. Baker, K. B., R. A. Greenwald, J. M. Ruohoniemi, J. R. Dedeny, M. Pinnock, N. Mattin, and J. M. Leonard, PACE, Polar Anglo-American Conjugate Experiment, EOS Trans. AGU, 70, 785, 1989.

    Article  Google Scholar 

  4. Cowley, S. W. H., M. P. Freeman, M. Lockwood, and M. F. Smith, The ionospheric signature of flux transfer events, in CLUSTER-Dayside Polar Cusp, ESA SP-330, pp. 105–112, ESTEC, Nordvijk, The Netherlands, 1991.

    Google Scholar 

  5. Detrick, D. L. and T. J. Rosenberg, A phased-array radio wave imager for studies of cosmic noise absorption, Radio Sci., 25, 325–338, 1990.

    Article  Google Scholar 

  6. Foster, J. C., Storm time plasma transport at middle and high latitude, J. Geophys. Res., 98, 1675–1689, 1993.

    Article  Google Scholar 

  7. Kirkwood, S., Modeling the undisturbed high-latitude region, Adv. Space Res., 13, 3, 101–104, 1993.

    Article  Google Scholar 

  8. Lockwood, M. and H. C. Carlson, Jr., Production of polar cap electron density patches by transient magnetopause reconnection, Geophys. Res. Lett., 19, 1731–1734, 1992.

    Article  Google Scholar 

  9. Lockwood, M. and M. F. Smith, The variation of reconnection rate at the dayside magnetopause and cusp ion precipitation, J. Geophys. Res., 97, 14,841–14,847, 1992.

    Article  Google Scholar 

  10. Lockwood, M., P. E. Sandholt, A. D. Farmer, S. W. H. Cowley, B. Lybekk, and V. N. Davda, Auroral and plasma flow transients at magnetic noon, Planet. Space Sci., 38, 8, 973–993, 1990.

    Article  Google Scholar 

  11. Lockwood, M., W. F. Denig, A. D. Farmer. V. N. Davda, S. W. H. Cowley, and H. Luhr, Ionospheric signatures of pulsed reconnection at the Earth’ magnetopause, Nature, 361, 4, 424–428, 1993.

    Article  Google Scholar 

  12. Newell, P. T. and C. I. Meng, Mapping the dayside ionosphere to the magnetosphere according to particle precipitation characteristics, Geophys. Res. Lett., 19, 6, 609–612, 1992.

    Article  Google Scholar 

  13. Nishino, M., Y. Tanaka, T. Oguti, H. Yamagishi, and J. A. Holtet, Initial observation results with imaging riometer at Ny-Alesund (L = 16), Proc. NIPR Symposium on Upper Atmosphere Physics, No. 6, 47–61, 1993.

  14. Nishino, M., H. Yamagishi, P. Stauning, T. J. Rosenberg, and J. A. Holtet, Location, spatial scale and motion of radio wave absorption in the cusp-latitude ionosphere observed by imaging riometers, J. Atmos. Terr. Phys., 59, 8, 903–924, 1997.

    Article  Google Scholar 

  15. Rodger, A. S., M. Pinnock, J. R. Dudeney, K. B. Baker, and R. A. Greenwald, A new mechanism for polar patch formation, J. Geophys. Res., 99, 6425–6436, 1994.

    Article  Google Scholar 

  16. Rosenberg, T. J., Z. Wang, A. S. Rodger, J. R. Dudeney, and K. B. Baker, Imaging riometer and HF radar measurements of drifting F region electron density structures in the polar cap, J. Geophys. Res., 98, 7757–7764, 1993.

    Article  Google Scholar 

  17. Russell, C. T. and R. C. Elphic, Initial ISEE magnetometer results: Magntopause observations, Space Sci. Rev., 22, 681–715, 1978.

    Article  Google Scholar 

  18. Sandholt, P. E., C. S. Dehr, A. Egeland, B. Lybekk, R. Viereck, and G. L. Romick, Signatures in the dayside aurora of plasma transfer from the magnetosheath, J. Geophys. Res.91, A9, 10,063–10,079, 1986.

    Article  Google Scholar 

  19. Setty, C. S. G. K., A. R. Jain, and M. K. Vyawahare, Collision frequency of electrons in the F-region, Can, J. Phys., 48, 653–658, 1970.

    Article  Google Scholar 

  20. Stauning, P., Absorption of cosmic noise in the E-region during electron heating events. A new class of riometer absorption events. Geophys. Res. Lett., 11, 1184–1187, 1984.

    Article  Google Scholar 

  21. Stauning, P., Investigations of ionospheric radio wave absorption processes using imaging riometer techniques, J. Atmos. Terr. Phys., 58, 6, 753–764, 1996a.

    Article  Google Scholar 

  22. Stauning, P., High-latitude D- and E-region investigations using imaging riometer observations, J. Atmos. Terr. Phys., 58, 6, 765–783, 1996b.

    Article  Google Scholar 

  23. Stauning, P. and J. K. Olesen, Observations of the unstable plasma in the disturbed polar E-region, Physica Scripta, 40, 325–332, 1989.

    Article  Google Scholar 

  24. Wang, Z., T. J. Rosenberg, P. Stauning, S. Basu, and G. Crowley, Calculations of riometer absorption associated with F region plasma structures based on Sondre Stromfjord incoherent scatter radar observations, Radio Sci., 29, 209–215, 1994.

    Article  Google Scholar 

  25. Yamagishi, H., M. Nishino, M. Sato, Y. Kato, M. Kojima, N. Sato, and T. Kikuchi, Development of imaging riometers, Antarctic Record, 36, 2, 227–250, 1992 (in Japanese).

    Google Scholar 

Download references

Author information

Affiliations

  1. Solar-Terrestrial Environment Laboratory, Nagoya University, Toyokawa, Japan

    Masanori Nishino & Satonori Nozawa

  2. Department of Physics, University of Oslo, Oslo, Norway

    Jan A. Holtet

Authors
  1. Masanori Nishino
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Satonori Nozawa
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Jan A. Holtet
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Masanori Nishino.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Nishino, M., Nozawa, S. & Holtet, J.A. Daytime ionospheric absorption features in the polar cap associated with poleward drifting F-region plasma patches. Earth Planet Sp 50, 107–117 (1998). https://doi.org/10.1186/BF03352092

Download citation

Keywords

  • Altitude Profile
  • Dayside Magnetopause
  • Ionospheric Absorption
  • Polar Cusp
  • Poleward Motion