LOGIN TO YOUR ACCOUNT

Username
Password
Remember Me
Or use your Academic/Social account:

CREATE AN ACCOUNT

Or use your Academic/Social account:

Congratulations!

You have just completed your registration at OpenAire.

Before you can login to the site, you will need to activate your account. An e-mail will be sent to you with the proper instructions.

Important!

Please note that this site is currently undergoing Beta testing.
Any new content you create is not guaranteed to be present to the final version of the site upon release.

Thank you for your patience,
OpenAire Dev Team.

Close This Message

CREATE AN ACCOUNT

Name:
Username:
Password:
Verify Password:
E-mail:
Verify E-mail:
*All Fields Are Required.
Please Verify You Are Human:
fbtwitterlinkedinvimeoflicker grey 14rssslideshare1
Lester , M.; Milan , S. E.; Besser , V.; Smith , R. (2001)
Publisher: European Geosciences Union
Languages: English
Types: Article
Subjects: Geophysics. Cosmic physics, Q, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, [ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere, Science, Physics, QC1-999, QC801-809

Classified by OpenAIRE into

arxiv: Physics::Space Physics, Physics::Geophysics
A comparison of HF radar backscatter observed by the CUTLASS Finland radar, meridian scanning photometer data from Longyearbyen, magnetic field variations from IMAGE stations, and particle precipitation measured by the DMSP F12 spacecraft is presented. The interval under discussion occurred in the pre-midnight local time sector, during a period of weakly northward interplanetary magnetic field. A region of HF backscatter, typically 8 degrees wide, occurred in the field of view of the CUTLASS Finland radar. A well defined gradient in the spectral width parameter was present, with mainly low (&lt; 200 m s - 1 ) spectral widths in the lower latitude part of the scatter and predominantly large (&gt; 200 ms - 1 ) spectral widths in the higher latitude part. The relationship between the spectral width and the red line (630.0 nm) emission measured by the meridian scanning photometer is considered. The poleward border of the red line emission, which has, in the past, been proposed as being representative of the polar cap boundary, was co-located to within 1° of magnetic latitude with the gradient in spectral width for part of the interval. Statistically, large spectral widths occurred poleward of the red line emission, while small spectral widths occurred within or equatorward of the red line emission. Near simultaneous DMSP particle observations in the 20 eV to 20 keV range indicate that the poleward border of the red line emission and the gradient in spectral width occurred at the same latitude as the transition from auroral oval to polar rain particle energies. We conclude that the large spectral widths were not caused by particle precipitation associated with the auroral oval. There were two periods of special interest when the relationship between the red line and the spectral width broke down. The first of these happened during enhanced red line and green line (557.7 nm) emission, with a drop out of the radar scatter and an enhanced, narrow westward electrojet. We conclude that this event was a magnetospheric substorm occurring at much higher than usual latitudes. The second period of special interest happened when equatorward moving bands of large spectral width occurred within the region of scatter. Up to 4 of these bands were present during an interval of 100 minutes. Associated with these narrow bands of large spectral width were narrow channels of enhanced westward ion velocities. We conclude that these equatorward moving bands of large spectral width may be related to reconnection processes in the tail. The observations demonstrate that the tail continues to be active even under low solar wind energy input conditions. Furthermore, we conclude that the gradient in the spectral width may be used as a proxy for the polar cap boundary, but only with extreme caution.<br><br><b>Key words. </b>Ionosphere (ionosphere-magnetosphere inter-actions; polar ionosphere) – Magnetospheric physics (storms and substorms)
  • The results below are discovered through our pilot algorithms. Let us know how we are doing!

    • Akasofu, S.-I., Polar and magnetospheric substorms, D. Reidel Publ. Co., Dordrecht, 1968.
    • Akasofu, S.-I., Perreault, P. D., Yasuhara, F., and Meng, C.-I., Auroral substorms and the interplanetary magnetic field, J. Geophys. Res., 78, 7490-7508, 1973.
    • André, R., Pinnock, M., and Rodger, A. S., On the SuperDARN autocorrelation function observed in the ionospheric cusp, Geophys. Res. Lett., 26, 3353-3356, 1999.
    • André, R., Pinnock, M., and Rodger, A. S., Identification of the low-altitude cusp by Super Dual Auroral Radar Network radars: A physical explanation for the empirically derived signature, J. Geophys. Res., 105, 27081-27093, 2000.
    • Baker, K. B. and Wing, S., A new magnetic co-ordinate system for conjugate studies at high latitude, J. Geophys. Res., 94, 9139- 9143, 1989.
    • Baker, K. B., Greenwald, R. A., Ruohoniemi, J. M., Dudeney, J. R., Pinnock, M., Newell, P. T., Greenspan, M. E., and Meng, C.- I., Simultaneous HF-radar and DMSP observations of the cusp, Geophys. Res. Lett., 17, 1869-1872, 1990.
    • Baker, K. B., Dudeney, J. R., Greenwald, R. A., Pinnock, M., Newell, P. T., Rodger, A. S., Mattin, N., and Meng, C.-I., HF radar signatures of the cusp and low latitude boundary layer, J. Geophys. Res., 100, 7671-7695, 1995.
    • Blanchard, G. T., Lyons, L. R., Samson, J. C. and Rich, F. J., Locating the polar cap boundary from observations of 6300 Å auroral emission, J. Geophys. Res., 100, 7855-7862, 1995.
    • Brittnacher, M. Filligam„ M., Parks, G., Germany, G., and Spann, J., Polar cap area and boundary motion during substorms, J. Geophys. Res., 104, 12251-12262, 1999.
    • Cowley, S. W. H., Excitation of flow in the Earth's magnetosphereionosphere system: Observations by incoherent-scatter radar, in Polar Cap Boundary Phenomena, Eds. J. Moen et al., pp 127- 140, Kluwer Academic Publishers, Netherlands, 1998.
    • Cowley, S. W. H. and Lockwood, M., Excitation and decay of solar wind-driven flows in the magnetosphere-ionosphere system, Ann. Geophysicae, 10, 103-115, 1992.
    • Craven, J. D. and Frank, L. A., Diagnosis of auroral dynamics using global aurora imaging with emphasis on large-scale fluctuations, in Auroral Physics, Eds. C.-I. Meng et al., pp 273-288, Cambridge University Press, Cambridge, 1991.
    • de la Beaujardiere, O., Lyons, L. R., Ruohoniemi, J. M., FriisChristensen, E., Danielsen, C., Rich, F. J., and Newell, P. T., Quiet-time intensifications along the poleward auroral boundary near midnight, J. Geophys. Res., 99, 287-298, 1994.
    • Dudeney, J. R., Rodger, A. S., Freeman, M. P., Pickett, J., Scudder, J., Sofko, G., and Lester, M., The nightside ionospheric response to IMF By changes, Geophys. Res. Lett., 25, 2601-2604, 1998.
    • Feldstein, Y. I. and Starkov, G. V., Dynamics of auroral belt and polar geomagnetic disturbances, Planet. Space Sci., 15, 209-230, 1967.
    • Fox, N. J., Cowley, S. W. H., Davda, V. N., Enno, G., FriisChristensen, E., Greenwald, R. A., Hairston, M. R., Lester, M., Lockwood, M., Lühr, H., Milling, D. K., Murphree, J. S., Pinnock, M., and Reeves, G. D., A multipont study of a substorm occurring on 7 December 1992 and its theoretical implications, Ann. Geophysicae, 17, 1369-1384, 1999.
    • Galperin, Yu. I. and. Feldstein, Ya. I, Auroral luminosity and its relationship to magnetospheric plasma domains, in Auroral Physics, Eds. C.-I. Meng et al., pp 207-222, Cambridge University Press, Cambridge, 1991.
    • Gazey, N. G. J., Lockwood, M., Smith, P. N., Coles, S., Bunting, R. J., Lester, M., Aylward, A. D., Yeoman, T. K., and Lühr, H., Development of substorm cross-tail current disruption as seen from the ground, J. Geophys. Res., 100, 9633-9648, 1995.
    • Greenwald, R. A., Baker, K. B., Dudeney, J. R., Pinnock, M., Jones, T. B., Thomas, E. C., Villain, J.-P., Cerisier, J.-C., Senior, C., Hanuise, C., Hunsucker, R. D., Sofko, G., Koehler, J., Nielsen, E., Pellinen, R., Walker, A. D. M., Sato, N., and Yamagishi, H., Darn/Superdarn: A global view of the dynamics of high-latitude convection, Space Sci. Rev., 71, 761-796, 1995.
    • Hardy, D. A., Gussenhoven, M. S., Riehl, K., Burkhardt, R., Heinemann, N., and Schumaker, T., The characteristics of polar cap precipitation and their dependence on the interplanetary magnetic field and the solar wind, in Solar Wind-Magnetosphere Coupling, Eds. Y. Kamide and J. A. Slavin, pp 575-604, Terra Sci. Pub. Co., Tokyo, 1986.
    • Holzworth, R. H. and Meng, C.-I., Mathematical representation of the auroral oval, Geophys. Res. Lett., 2, 377-380, 1975.
    • Kamide, Y. and Kokubun, S., Two-component auroral electrojet: Importance for substorm studies, J. Geophys. Res., 101, 13027- 14046, 1996.
    • Lepping, R. P., Acuna, M. H., Burlaga, L. F., Farrell, W. M., Slavin, J. A., Schatten, K. H., Mariani, F., Ness, N. F., Neubauer, F. M., Whang, Y. C., Byrnes, J. B., Kennon, R. S., Panetta, P. V., Scheifele, J., and Worley, E. M., The Wind magnetic field investigation, Space Sci. Rev., 71, 207-229, 1995.
    • Lester, M., HF coherent scatter radar observations of ionospheric convection during magnetospheric substorms, Adv. Polar Upper Atmos. Res., 14, 179-201, 2000.
    • Lester, M., Freeman, M. P., Southwood, D. J., Waldock, J. A., and Singer, H. J., A study of the relationship between interplanetary parameters and large displacements of the nightside polar cap, J. Geophys. Res., 95, 21133-21145, 1990.
    • Lester M., Lockwood, M., Yeoman, T. K., Cowley, S. W. H., Lühr, H., Bunting, R., and Farrugia, C. J., The response of ionospheric convection in the polar cap to substorm activity, Ann. Geophysicae, 13, 147-158, 1995.
    • Lester, M., Jones, T. B., Robinson, T. R., Thomas, E. C., Yeoman, T. K., Pellinen, R., Huuskonen, A., Opgenoorth, H., Persson, M., Pellinen-Wannberg, A., and Haggstrom, I., CUTLASS - A tool for co-ordinated space/ground based investigations of the solar terrestrial system, in Satellite - Ground Based Coordination Sourcebook, ESA-SP-1198, 191-202, Eds. M. Lockwood, M. N. Wild and H. J. Opgenoorth, ESA Publications, ESTEC, Noordwijk, The Netherlands, 1997.
    • Lester, M., Milan, S. E., Baker, K., Greenwald, R. A., Brittnacher, M., Lummerzheim, D., Owen, D., Pulkinnen, T., Reeves, G. D., Sofko, G., and Villain, J.-P., Polar, IMP-8 and SuperDARN observations of substorm growth and expansion phase signatures, SUBSTORMS-4 (Eds. S. Kokubun and Y. Kamide), 175-178, Terra Scientific Publishing Corporation, 1998.
    • Lewis, R. V., Freeman, M. P., Rodger, A. S., Reeves, G. D., and Milling, D. K., The electric field response to the growth phase and expansion phase onset of a small isolated substorm, Ann. Geophysicae, 15, 289-299, 1997.
    • Lockwood, M., Cowley, S. W. H., Todd, H., Willis, D. M., and Clauer, C. R., Ion flows and heating at a contracting polar cap boundary, Planet. Space Sci., 36, 1229-1253, 1988.
    • Milan, S. E., Davies, J. A., and Lester, M., Coherent HF radar backscatter characteristics associated with auroral forms identified by incoherent radar techniques, J. Geophys. Res., 104, 22591-22603, 1999.
    • Newell, P. T., Feldstein, Y. I., Galperin, Y. I., and Meng, C.-I., Morphology of nightside precipitation, J. Geophys. Res., 101, 10737-10748, 1996.
    • Nishida, A., Interplanetary origin of electric fields in the magnetosphere, Cosmic Electrodyn., 2, 350, 1971.
    • Ogilvie, K. W., Chornay, D. J., Fritzenreiter, R. J., Hunsaker, F., Keller, J., Lobell, J., Miller, G., Scudder, J. D., Sittler Jr., E. C., Torbert, R. B., Bodet, D., Needell, G., Lazarus, A. J., Steinberg, J. T., Tappan, J. H., Mavretic, A., and Gergin, E., SWE, A comprehensive plasma instrument for the Wind spacecraft, Space Sci. Rev., 71, 55-77, 1995.
    • Persson, M. A. L., Aikio, A. T., and Opgenoorth, H., Satellitegroundbased coordination: late growth and early expansion phase of a substorm, in Proc. Second Internat. Conf. on Substorms, Geophys. Institute, Fairbanks, Alaska, pp 157, 1994.
    • Petrukovich, A. A., Baumjohann, W., Nakamura, R., Mukai, T., and Troshichev, O. A., Small substorms: Solar wind input and magnetotail dynamics, J. Geophys. Res., 105, 21109-21118, 2000.
    • Reiff, P. H. and Burch, J. L., IMF By -dependent plasma flow and Birkeland currents in the dayside magnetopshere. 2. A global model for northward and southward IMF, J. Geophys. Res., 90, 1595-1609, 1985.
    • Ruohoniemi, J. M. and Baker, K. B., Large-scale imaging of highlatitude convection with Super Dual Auroral radar Network HF radar observations, J. Geophys. Res., 103, 20797-20806, 1998.
    • Samson, J. C., Lyons, L. R., Xu, B., Creutzberg, F., and Newell, P., Proton aurora and substorm intensifications, Geophys. Res. Letts., 19, 2167-2170, 1992.
    • Taylor, J. R., Yeoman, T. K., Lester, M., Emery, B. A., and Knipp, D. J., Variations in the polar cap area during intervals of substorm activity on 20-21 March 1990 deduced from AMIE convection patterns, Ann. Geophysicae, 14, 879-887, 1996.
    • Tsyganenko, N. A., Quantitative models of the magnetospheric magnetic field: methods and results, Space Sci. Rev., 54, 75- 104, 1990.
    • Viljanen, A. and Häkkinen, L., IMAGE magnetometer network, in Satellite - Ground Based Coordination Sourcebook, ESASP-1198, 111-118, Eds. M. Lockwood, M. N. Wild and H. J. Opgenoorth, ESA Publications, ESTEC, Noordwijk, The Netherlands, 1997.
    • Winningham, J. D., Yashura, F., Akasofu, S.-I., and Heikkila, W., The latitudinal morphology of 10-eV to 10-keV electron fluxes during magnetically quiet and disturbed times in the 2100-0300 MLT sector, J. Geophys. Res., 80, 3148-3160, 1975.
    • Yeoman, T. K., Davies, J. A., Wade, N. M., Provan, G., and Milan, S. E., Combined CUTLASS, EISCAT and ESR observations of an isolated substorm, Ann. Geophysicae, 18, 1073-1087, 2000.
  • No related research data.
  • No similar publications.