Main Article Content
A theoretical model is proposed which describes the influence of non-uniform ionospheric height-integrated conductivity distributions on VLF-pulsations. The assumption is made that the field-aligned currents carried by the wave-field are closed by polarisation currents in the magnetosphere and by the irrotational part of the height-integrated ionospheric currents. Current continuity at the magnetosphere-ionosphere boundary provides for a differential equation governing the reflected electric field for arbitrary non-uniform conductivity distributions. Model calculations for simple, but realistic conductivity and electric field distributions show that local shifts of the ionospheric field maximum against that of the magnetic field below the ionosphere as well as double-peak distributions of the electric field can occur. Strong electric field anomalies i.e. significant deviations of the electric field distribution as compared with the uniform case occur in conductivity gradient zones and fall off rapidly outside. The previously predicted 90° rotation between the magnetic field below and above the ionosphere does not hold generally because the rotation angle depends strongly on the conductivity gradients.
Authors who publish with this journal as of Vol. 63 agree to the following terms:
a. Authors share the copyright with this journal in equal parts (50% to the journal, 50% to the lead author), and grant the journal right of first publication, with the work after publication simultaneously licensed under Creative Commons Attribution License CC BY-NC-ND 4.0 that allows others to share the work with an acknowledgment of the work's authorship and initial publication in this journal.
b. Authors may enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgment of its initial publication in this journal, and a reference to this copyright notice.
c. Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) during the submission process, as this can lead to productive exchanges and earlier and greater citation of published work and better sales of the copyright.
Authors retain copyright and grant the Journal of Geophysics right of first publication, with the work two years after publication simultaneously licensed under the Creative Commons BY-NC-ND 4.0 License that allows others to share the work (with an acknowledgment of the work's authorship and initial publication in this journal), except for commercial purposes and for creating derivatives.
Authors can enter into separate, additional, but non-commercial contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository, but not publish it in a book), with an acknowledgment of its initial publication in this journal.
Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) before and during the submission process, as that can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
This journal is one of a handful of scholarly journals that publish original scientific works under CC BY-NC-ND 4.0 - the only Creative Commons license affording the authors' intellectual property absolute worldwide protection.
Journal of Geophysics is published under the scholar-publishers model, meaning authors do not surrender their copyright to us. Instead, and unlike corporate publishers like Elsevier or Springer Nature that resell copyright to third-parties for up to $80,000 (per paper, per transaction!), the Journal of Geophysics authors share copyright equally with this journal.
Therefore, all the proceeds from reselling copyright to third parties get shared to equal parts (50% to the journal, 50% to the lead author). Under the Berne Convention, this protection is an inheritable right that lasts for as long as the rightsholder lives + 50 years.
By submitting to this journal, the lead author, on behalf of all co-authors, grants permission to this journal to represent all co-authors in negotiating copyright sales and collecting proceeds. The lead author should negotiate with his/her co-authors the modalities of distributing the lead author's portion of the proceeds. Usually, this is per pre-agreed percentage of each co-author's contribution to creating the copyrighted work. (more...)
Bostrom, R. (1964) A model of the auroral electrojets. J. Geophys. Res. 69:4983-5000
Bostrom, R. (1972) Magnetosphere-ionosphere coupling. In: Dyer, E.R. (Ed.) Critical Problems of Magnetospheric Physics, pp 139-156, IUCSTP Secretariat, National Academy of Sciences, Washington D.C.
Chapman, S., Bartels, J. (1940) Geomagnetism. Oxford University Press
Chen, F.F. (1974) Introduction to plasma physics. Plenum Press, New York
Duschek, A., Hochrainer, A. (1961) Tensorrechnung in analytischer Darstellung. Vol. 2: Tensoranalysis. Springer Verlag
Doupnik, J.R., Brekke, A., Banks, P.M. (1977) Incoherent scatter radar observations during three sudden commencements and a Pc5 event on August 4, 1972. J. Geophys. Res. 82:499-514
Drell, S.D., Foley, H.M., Ruderman, M.A. (1965) Drag and propulsion of large satellites in the ionosphere: An Alfven propulsion engine in space. J. Geophys. Res. 70:3131-3146
Dungey, J. (1963) Hydromagnetic waves and the ionosphere, Proc. Int. Conference on the Ionosphere, pp. 230-232, Inst. Physics, London
Ellis, P., Southwood, D.J. (1983) Reflection of Alfven-waves by nonuniform ionospheres. Planet. Space Sci. 31:107-117
Fejer, J.A., Krenzien, E. (1983) Theory of generation of ULF pulsations by ionospheric modification experiments. J. Atmos. Terr. Phys. 44:1075-1087
Fukushima, N. (1976) Generalized theorem of no ground magnetic effect of vertical currents connected with Pedersen currents in the uniform conductivity ionosphere. Rep. Ionos. Space Res. Jpn. 30:35-40
Glasmeier, K.H., Nielsen, E., Kuppers, F. (1981) Magnetometer array observation of a pulsation event in the Pc5 frequency band (abstract only). IAGA Sci. Ass., Edinburgh
Glasmeier, K.H. (1983) Reflection of MHD-waves in the Pc4-5 period range at ionospheres with non-uniform conductivity distributions. Geophys. Res. Lett., 10:678-681
Goertz, C.K. (1980) Io's interaction with the plasma torus. J. Geophys. Res. 85:2949-2956
Greenwald, R.A., Walker, A.D.M. (1980) Energetics of long period resonant hydromagnetic waves. Geophys. Res. Lett. 7:745-748
Hasegawa, A., Lanzerotti, L.J. (1978) On the orientati0n of hydromagnetic waves in the magnetosphere. Rev. Geophys. Space Phys. 16:263-266
Hughes, W.J. (1974) The effect of the atmosphere and ionosphere on long period magnetospheric micropulsations. Planet. Space Sci. 22:1157-1172
Hughes, W.J., Southwood, D.J. (1976) The screening of micropulsation signals by the atmosphere and ionosphere. J. Geophys. Res. 81:3234-3240
Inoue, Y. (1973) Wave polarisations of geomagnetic pulsations observed in high latitudes on the earth's surface. J. Geophys. Res. 78:2959-2976
Kuppers, F., Untiedt, J., Baumjohann, W., Lange, K., Jones, A.G. (1979) A two-dimensional magnetometer array for groundbased observations of auroral zone electric currents during the International Magnetospheric Study (IMS). J. Geophys. 46:429-450
Luzemann, M. (1982) Electrodynamic interaction of the satellite Io with the Jovian magnetosphere. Gamma 39, lnstitut f. Geophysik u. Meteorologie, Braunschweig
Mallinckrodt, A.J., Carlson, C.W. (1978) Relations between transverse electric fields and field-aligned currents. J. Geophys. Res. 83:1426-1432
Maltsev, Yu.P., Leontyev, S.V., Lyatsky, W.B. (1974) Pi2 pulsations as a result of evolution of an Alfven impulse originating in the ionosphere during a brightening of aurora. Planet. Space Sci. 22:1519-1533
Mersmann, U., Baumjohann, W., Kuppers, F. (1979) Analysis of an eastward electrojet by means of upward continuation of ground-based magnetometer data. J. Geophys. 45:281-298
Mitchell, A.R., Griffiths, D.F. (1980) The finite difference method in partial differential equations. Wiley and Sons
Neubauer, F.M. (1980) Nonlinear standing Alfven wave current system at lo: Theory. J. Geophys. Res. 85:1171-1178
Newton, R.S., Southwood, D.J., Hughes, W.J. (1978) Damping of geomagnetic pulsations by the ionosphere. Planet. Space Sci. 26:201-209
Nielsen, E., Allan, W. (1983) A double-resonance Pc5 pulsation. J. Geophys. Res. 88:5760-5764
Nishida, A. (1964) Ionospheric screening effect and storm sudden commencement. J. Geophys. Res. 69:1861-1874
Poulter, E.M., Nielsen, E., Potemra, T.A. (1982) Field-aligned currents associated with Pc5 pulsations: ST ARE and TRIAD observations. J. Geophys. Res. 87:2331-2336
Saka, 0., ltonga, M., Kitamura, T. (1982) Ionospheric control of polarisation of low-latitude geomagnetic micropulsations at sunrise. J. Atmos. Terr. Phys. 44:703-712
Siebert, M., Kertz, W. (1957) Zur Zerlegung eines lokalen erdmagnetischen Feldes in au13eren und inneren Anteil. Nachr. Akad. Wiss. Gottingen 1957, Math.-Phys. Kl. 87-112
Southwood, D.J. (1974) Some features of field line resonances in the magnetosphere. Planet. Space Sci. 22:483-491
Stubbe, P., Kopka, H. (1977) Modulation of the polar electrojet by powerful HF waves, J. Geophys. Res. 82:2319-2325
Tamao, T. (1965) Transmission and coupling resonance of hydromagnetic disturbances in the non-uniform earth's magnetosphere. Sci. Rep. Tohoku Univ., Ser 5, Geophysics, Vol. 17(2):43-72
Vasyliunas, V.M. (1970) Mathematical models of magnetospheric convection and its coupling to the ionosphere. In: McCormac, B.M. (Ed.) Particles and fields in the magnetosphere, pp 60-74. D. Reidel, Dordrecht
Vickrey, J.F., Vondrak, R.R., Mathews, S.J. (1981) The diurnal and latitudinal variation of auroral zone ionospheric conductivity. J. Geophys. Res. 86,:65-75
Walker, A.D.M., Greenwald, R.A., Stuart, W.F., Green, C.A. (1979) ST A RE auroral radar observations of Pc5 geomagnetic pulsations. J. Geophys. Res. 84:3373-3388
Weaver, J.T. (1964) On the separation of local geomagnetic fields into external and internal parts. J. Geophys. 30:29-36