ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Copernicus Publications Göttingen, Germany 10.5194/angeo-27-3591-2009 Cluster spacecraft observations of a ULF wave enhanced by Space Plasma Exploration by Active Radar (SPEAR) Badman S. V. 1 Wright D. M. 1 Clausen L. B. N. 1 Fear R. C. 1 Robinson T. R. 1 Yeoman T. K. 1 Department of Physics & Astronomy, University of Leicester, Leicester LE1 7RH, UK 28 09 2009 27 9 3591 3599 Copyright: © 2009 S. V. Badman et al. 2009 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://angeo.copernicus.org/articles/27/3591/2009/angeo-27-3591-2009.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/27/3591/2009/angeo-27-3591-2009.pdf

Space Plasma Exploration by Active Radar (SPEAR) is a high-latitude ionospheric heating facility capable of exciting ULF waves on local magnetic field lines. We examine an interval from 1 February 2006 when SPEAR was transmitting a 1 Hz modulation signal with a 10 min on-off cycle. Ground magnetometer data indicated that SPEAR modulated currents in the local ionosphere at 1 Hz, and enhanced a natural field line resonance with a 10 min period. During this interval the Cluster spacecraft passed over the heater site. Signatures of the SPEAR-enhanced field line resonance were present in the magnetic field data measured by the magnetometer on-board Cluster-2. These are the first joint ground- and space-based detections of field line tagging by SPEAR.

 References Balogh, A., Carr, C. M., Acuña, M. H., Dunlop, M. W., Beek, T. J., Brown, P., Fornacon, K.-H., Georgescu, E., Glassmeier, K.-H., Harris, J., Musmann, G., Oddy, T., and Schwingenschuh, K.: The Cluster Magnetic Field Investigation: overview of in-flight performance and initial results, Ann. Geophys., 19, 1207–1217, 2001. Belyaev, P. P., Polyakov,&nbsp;S. V., Rapoport,&nbsp;V. O., and Trakhtengerts,&nbsp;V. Y.: Discovery of resonance structure in the spectrum of atmospheric electromagnetic background noise in the range of short-period geomagnetic pulsations, Dokl. Akad. Nauk SSSR, 297, 840–846, 1987. Belyaev, P. P., Bösinger,&nbsp;T., Isaev,&nbsp;S. V., and Kangas, J.: First evidence at high latitudes for the ionospheric Alfvén resonator, J. Geophys. Res., 104(A3), 4305–4317, 1999. Borisov,&nbsp;N. and Stubbe, P.: Excitation of longitudinal (field-aligned) currents by modulated HF heating of the ionosphere, J. Atmos. Solar Terr. Phys., 59(15), 1973–1989, 1997. Bösinger,&nbsp;T., Kero,&nbsp;A., Pollari,&nbsp;P., Pashin,&nbsp;A., Belyaev,&nbsp;P., Rietveld,&nbsp;M., Turunen,&nbsp;T., and Kangas,&nbsp;J.: Generation of artificial magnetic pulsations in the Pc1 frequency range by periodic heating of the Earth's ionosphere: indications of Alfven resonator effects, J. Atmos. Solar Terr. Phys., 62(4), 277–297, 2000. Carlson,&nbsp;C. W., Pfaff,&nbsp;R. F., and Watzin,&nbsp;J. G.: The Fast Auroral SnapshoT (FAST) Mission, Geophys. Res. Lett., 25(12), 2013–2016, 1998. Chisham,&nbsp;G. and Orr, D.: Statistical studies of giant mode pulsations (Pgs): harmonic mode, Planet. Space Sci., 39, 999–1006, 1991. Clausen,&nbsp;L. B. N., Yeoman,&nbsp;T. K., Wright,&nbsp;D. M., Robinson,&nbsp;T. R., Dhillon,&nbsp;R. S., and Gane,&nbsp;S. C.: First results of a ULF wave injected on open field lines by Space Plasma Exploration by Active Radar (SPEAR), J. Geophys. Res., 113, A01305, https://doi.org/10.1029/2007JA012617, 2008. Escoubet,&nbsp;C. P., Fehringer, M., and Goldstein,&nbsp;M.: The Cluster mission, Ann. Geophys., 19, 1197–1200, 2001. Fenrich, F. R., Samson,&nbsp;J. C., Sofko,&nbsp;G., and Greenwald,&nbsp;R. A.: ULF High- and Low-<i>m</i> Field Line Resonances observed with the Super Dual Auroral Radar Network, J. Geophys. Res., 100(A11), 21535–21547, 1995. Gustafsson,&nbsp;G., Boström,&nbsp;R., Holback,&nbsp;B., Holmgren,&nbsp;G., Lundgren,&nbsp;A., Stasiewicz,&nbsp;K., Åhlén,&nbsp;L., Mozer,&nbsp;F. S., Pankow,&nbsp;D., Harvey,&nbsp;P., Berg,&nbsp;P., Ulrich,&nbsp;R., Pedersen,&nbsp;A., Schmidt,&nbsp;R., Butler,&nbsp;A., Fransen,&nbsp;A. W. C., Klinge,&nbsp;D., Thomsen, M., Fälthammar,&nbsp;C.-G., Lindqvist,&nbsp;P.-A., Christenson,&nbsp;S., Holtet, J., Lybekk,&nbsp;B., Sten,&nbsp;T. A., Tanskanen,&nbsp;P., Lappalainen,&nbsp;K.,&nbsp;and Wygant, J.: The Electric Field and Wave Experiment for the Cluster Mission, Space Sci. Rev., 79, , https://doi.org/10.1023/A:1004923124586, 1995. Holzworth,&nbsp;R. H. and Meng, C.-I.: Mathematical representation of the auroral oval, Geophys. Res. Lett., 2(9), 377–380, 1975. Hughes,&nbsp;W. H. and Southwood,&nbsp;D. J.: The screening of micropulsation signals by the atmosphere and ionosphere, J. Geophys. Res., 81(19), 3234–3240, 1976. Johnstone,&nbsp;A. D., Alsop,&nbsp;C., Burdge,&nbsp;S., Carter,&nbsp;P. J., Coates,&nbsp;A. J., Coker,&nbsp;A. J., Fazakerley,&nbsp;A. N., Grande,&nbsp;M., Gowen,&nbsp;R. A., Gurgiolo,&nbsp;C., Hancock,&nbsp;B. K., Narheim,&nbsp;B., Preece,&nbsp;A., Sheather,&nbsp;P. H., Winningham,&nbsp;J. D.,&nbsp;and Woodliffe,&nbsp;R. D.: PEACE: A Plasma Electron And Current Experiment, Space Sci. Rev., 79, 351–398, 1997. Lühr, H.: The IMAGE magnetometer network, STEP Int. Newsl., 4, 4, 1994. Lysak, R. L.: Generalised model of the ionospheric Alfvén resonator, in: Auroral Plasma Dynamics, edited by: Lysak, R. L., 121–128, AGU, Washington, D. C., 1993. Maul,&nbsp;A.-A., Rietveld,&nbsp;M.T., Stubbe,&nbsp;P., and Kopka,&nbsp;H.: Excitation of periodic magnetic field oscillations in the ULF range by amplitude modulated HF waves, Ann.&nbsp;Geophys., 8, 765–780, 1990. Ogilvie, K. W., Chornay,&nbsp;D. J., Fritzenreiter,&nbsp;R. J., Hunsaker,&nbsp;F., Keller,&nbsp;J., Lobell,&nbsp;J., Miller,&nbsp;G., Scudder,&nbsp;J. D., Sittler&nbsp;Jr.,&nbsp;E. C., Torbert,&nbsp;R. B., Bodet,&nbsp;D., Needell,&nbsp;G., Lazarus,&nbsp;A. J., Steinberg,&nbsp;J. T., Tappan,&nbsp;J. H., Mavretic,&nbsp;A., and Gergin,&nbsp;E.: SWE, a comprehensive plasma instrument for the WIND spacecraft, Space Sci. Rev. 71, 55– , 1995. Orr, D.: Magnetospheric hydromagnetic waves: their eigenperiods, amplitudes and phase variations; a tutorial introduction, J.&nbsp;Geophys., 55, 76–84, 1984. Robinson,&nbsp;T. R., Strangeway,&nbsp;R., Wright,&nbsp;D. M., Davies,&nbsp;J. A., Horne,&nbsp;R. B., Yeoman,&nbsp;T. K., Stocker,&nbsp;A. J., Lester,&nbsp;M., Rietveld,&nbsp;M. T., Mann,&nbsp;I. R., Carlson,&nbsp;C. W., and McFadden, J. P.: FAST observations of ULF waves injected into the magnetosphere by means of modulated RF heating of the auroral electrojet, Geophys. Res. Lett., 27, 3165–3168, 2000. Robinson, T. R., Yeoman, T. K., Dhillon, R. S., Lester, M., Thomas, E. C., Thornhill, J. D., Wright, D. M., van Eyken, A. P., and McCrea, I. W.: First observations of SPEAR-induced artificial backscatter from CUTLASS and the EISCAT Svalbard radars, Ann. Geophys., 24, 291–309, 2006. Scoffield, H. C., Yeoman,&nbsp;T. K., Robinson,&nbsp;T. R., Baddeley,&nbsp;L. J., Dhillon,&nbsp;R. S., Wright,&nbsp;D. M., Raita,&nbsp;T., and Turunen,&nbsp;T.: First results of artificial stimulation of the ionospheric Alfvén resonator at 78° N, Geophys. Res. Lett., 33, L19103, https://doi.org/10.1029/2006GL027384, 2006. Smith,&nbsp;C. W., Acuña,&nbsp;M. H., Burlaga,&nbsp;L. F., L'Heureux,&nbsp;J., Ness,&nbsp;N. F., and Scheifele,&nbsp;J.: The ACE Magnetic Field Experiment, Space Sci. Rev., 86, 613–622, 1999. Stone, E. C., Frandsen,&nbsp;A. M., Mewaldt,&nbsp;R. A., Christian,&nbsp;E. R., Margolies,&nbsp;D., Ormes,&nbsp;J. F., and Snow,&nbsp;F.: The Advanced Composition Explorer, Space Sci. Rev., 86, 1–22, 1998. Stubbe, P.: Review of ionospheric modification experiments at Tromsø, J. Atmos. Terr. Phys., 58, 349–368, 1996. Stubbe, P., Kopka,&nbsp;H., Rietveld,&nbsp;M. T., and Dowden,&nbsp;R. L.: ELF and VLF wave generation by modulated HF heating of the current carrying lower ionosphere, J. Atmos. Terr. Phys., 44, 1123–1131, 1982. Tsyganenko, N. A.: Effects of the solar wind conditions on the global magnetospheric configuration as deduced from data-based field models, Eur. Space Agency Spec. Publ., ESA SP-389, 181, 1996. Wright, D. M., Davies, J. A., Robinson, T. R., Chapman, P. J., Yeoman, T. K., Thomas, E. C., Lester, M., Cowley, S. W. H., Stocker, A. J., Horne, R. B., and Honary, F.: Space Plasma Exploration by Active Radar (SPEAR): an overview of a future radar facility, Ann. Geophys., 18, 1248–1255, 2000.