References

ANGEO

Annales Geophysicae

ANGEO

Ann. Geophys.

1432-0576

Copernicus Publications

Göttingen, Germany

10.5194/angeo-24-3071-2006

Characteristics of merging at the magnetopause inferred from dayside 557.7-nm all-sky images: IMF drivers of poleward moving auroral forms

Maynard

N. C.

¹ Burke

W. J.

² Ebihara

³ Ober

D. M.

⁴ ¹⁰ Wilson

G. R.

⁴ ¹¹ Siebert

K. D.

⁴ ¹² Winningham

J. D.

⁵ Lanzerotti

L. J.

⁶ Farrugia

C. J.

¹ Ejiri

³ Rème

⁷ Balogh

⁸ Fazakerley

⁹

Space Science Center, University of New Hampshire, Durham, NH, USA

Air Force Research Laboratory, Hanscom Air Force Base, MA, USA

National Institute of Polar Research, Tokyo, Japan

ATK Mission Research, Nashua, NH, USA

Southwest Research Institute, San Antonio, TX, USA

New Jersey Institute of Technology, NJ, USA

CESR/CNRS, Avenue du Colonel Roche, 31028 Toulouse, Cedex 4, France

Imperial College, Exhibition Road, London SW7 2BW, UK

Mullard Space Science Laboratory, Dorking, Surrey RH5 6NT, UK

now at: Boston College, Chestnut Hill, MA, USA

now at: Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL, USA

now at: SPARTA, Inc., Nashua, NH, USA

22 11 2006

24 11 3071 3098

2006

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/24/3071/2006/angeo-24-3071-2006.html

The full text article is available as a PDF file from https://angeo.copernicus.org/articles/24/3071/2006/angeo-24-3071-2006.pdf

We combine in situ measurements from Cluster with high-resolution 557.7 nm all-sky images from South Pole to investigate the spatial and temporal evolution of merging on the dayside magnetopause. Variations of 557.7 nm emissions were observed at a 6 s cadence at South Pole on 29 April 2003 while significant changes in the Interplanetary Magnetic Field (IMF) clock angle were reaching the magnetopause. Electrons energized at merging sites are the probable sources for 557.7 nm cusp emissions. At the same time Cluster was crossing the pre-noon cusp in the Northern Hemisphere. The combined observations confirm results of a previous study that merging events can occur at multiple sites simultaneously and vary asynchronously on time scales of 10 s to 3 min (Maynard et al., 2004). The intensity of the emissions and the merging rate appear to vary with changes in the IMF clock angle, IMF BX and the dynamic pressure of the solar wind. Most poleward moving auroral forms (PMAFs) reflect responses to changes in interplanetary medium rather than to local processes. The changes in magnetopause position required by increases in dynamic pressure are mediated by merging and result in the generation of PMAFs. Small (15–20%) variations in dynamic pressure of the solar wind are sufficient to launch PMAFs. Changes in IMF BX create magnetic flux compressions and rarefactions in the solar wind. Increases (decreases) in IMF BX strengthens |B| near northern (southern) hemisphere merging sites thereby enhancing merging rates and triggering PMAFs. When correlating responses in the two hemispheres, the presence of significant IMF BX also requires that different lag-times be applied to ACE measurements acquired ~0.1 AU upstream of Earth. Cluster observations set lag times for merging at Northern Hemisphere sites; post-noon optical emissions set times of Southern Hemisphere merging. All-sky images and magnetohydrodynamic simulations indicate that merging occurs in multiple discrete locations, rather than continuously, across the dayside for southward IMF conditions in the presence of dipole tilt. Matching optical signatures with clock-angle, BX, and dynamic pressure variations provides new insights about interplanetary control of dayside merging and associated auroral dynamics.

References 1

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.

Basinska, E. M., Burke, W. J., and Heinemann, M. A.: A user's guide to locating flux transfer events in low-altitude satellite measurements: An S3-2 case study, J. Geophys. Res., 94, 6681–6691, 1989.

Bosqued, J. M., Escoubet, C. P., Frey, H. U., Dunlop, M., Berchem, J., Marchaudon, A., Cerisier, J. C., Fazakerley, A., Budnik, E., Lavraud, B., Rème, H., Laakxso, H., and Balogh, A.: Multipoint observations of transient reconnection signatures in the cusp precipitation: A Cluster-IMAGE detailed case study, J. Geophys. Res., 110, A03219, https://doi.org/10.1029/2004JA010621, 2005.

Cerisier, J. C., Masrchaudon, A., Bosqued, J. M., McWilliams, K., Frey, H. U., Bouhram, M., Laakso, H., Dunlop, M., Forster, M., and Fazakerley, A.: Ionospheric signatures of plasma injections in the cusp triggered by solar wind pressure pulses, J. Geophys. Res., 110, A08204, https://doi.org/10.1029/2004JA010962, 2005.

Coleman, I. J., Chisham, G., Pinnock, M., and Freeman, M. P.: An ionospheric convection signature of antiparallel reconnection, J. Geophys. Res., 106, 28 995–29 007, 2001.

Cowley, S. W. H. and Lockwood, M.: Excitation and decay of solar wind driven flows in the magnetosphere-ionosphere system, Ann. Geophys., 10, 103–115, 1992.

Crooker, N. U.: Dayside merging and cusp geometry, J. Geophys. Res., 84, 951–959, 1979.

Denig, W. F., Burke, W. J., Maynard, N. C., Rich, F. J., Jacobsen, B., Sandholt, P. E., Egeland, A., Leontjev, S., and Vorobjev, V. G.: Ionospheric signatures of dayside magnetopause transients: A case study using satellite and ground measurements, J. Geophys. Res., 98, 5969–5980, 1993.

Fasel, G. J.: Dayside poleward moving auroral forms: A statistical study, J. Geophys. Res., 11 891–11 905, 1995.

Friis-Christensen, E., McHenry, M. A., Clauer, C. R., and Vennerstrom, S.: Ionospheric traveling convection vortices observed near the polar cleft: A triggered response to sudden changes in the solar wind, Geophys. Res. Lett., 15, 253–256, 1988.

Gonzalez, W. D. and Mozer, F. S.: A quantitative model for the potential resulting from reconnection with arbitrary interplanetary magnetic field, J. Geophys. Res., 79, 4186–4194, 1974.

Gosling, J. T., Thomsen, M. F., Bame, S. J., Onsager, T. G., and Russell, C. T.: The electron edge of the low latitude boundary layer during accelerated flow events, Geophys. Res. Lett., 17, 1833–1836, 1990.

Gustafsson, G., Boström, R., Holback, B., Holmgren, G., Lundgren, A., Stasiewicz, K., Åhlén, Mozer, F. S. W., Pankow, D., Harvey, P., Berg, P., Ulrich, R., Pedersen, A., Schmidt, R., Butler, A., Fransen, A. W. C., Klinge, D., Thomsen, M., Fälthammar, C.-G., Lindqvist, P.-A., Christenson, S., Holtet, J., Lybekk, B., Sten, T. A., Tanskanen, P., Lappalainen, K., and Wygant, J.: The electric field and wave experiment for the Cluster mission, Space Sci. Rev., 79, 137–156, 1997.

Hain, K.: The partial donor cell method, J. Comp. Physics, 73, 131–147, 1987.

Johnstone, A. D., Alsop, C., Burge, S., Carter, P. J., Coates, A. J., Coker, A. J., Fazakerley, A. N., Grande, M., Gowen, R. A., Gurgiolo, C., Hancock, B. K., Narheim, B., Preece, A., Sheather, P. H., Winningham, J. D., and Woodliffe, R. D.: PEACE: A plasma electron and current experiment, Space Sci. Rev., 79, 351–398, 1997.

Katoaka, R., Fukunishi, H., Lanzerotti, L. J., Maclennan, C. G., Frey, H. U., Mende, S. B., Doolittle, J. H., Rosenberg, T. J., and Weatherwax, A. T.: Magnetic impulse events: A detailed case study of extended ground and space observations, J. Geophys. Res., 106, 25 873–25 889, 2001.

Kataoka, R., Fukunishi, H., and Lanzerotti, L. J.: Statistical identification of solar wind origins of magnetic impulse events, J. Geophys. Res., 108(A12), 1436, https://doi.org/10.1029/2003JA010202, 2003.

Kivelson, M. G. and Southwood, D. J.: Ionospheric traveling vortex generation by solar wind buffeting of the magnetosphere, J. Geophys. Res., 96, 1661–1667, 1991.

Konik, R. M., Lanzerotti, L. J., Wolfe, A., Maclennan, C. G., and Venkatesan, D.: Cusp latitude magnetic impulse events, 2. Interplanetary magnetic field and solar wind conditions, J. Geophys. Res., 99, 14 831–14 853, 1994.

Korotova, G. I., Sibeck, D. G., Moretto, T., and Reeves, G. D.: Tracking transient events through geosynchronous orbit, J. Geophys. Res., 104, 10 265–10 273, 1999.

Korotova, G. I., Sibeck, D. G., Singer, H. J., Rosenberg, T. J., and Engebretson, M. J.: Interplanetary magnetic field control of dayside transient event occurrence and motion in the ionosphere and magnetosphere, Ann. Geophys., 22, 4197–4202, 2004.

Lanzerotti, L. J., Lee, L. C., Maclennan, C. G., Wolfe, A., and Medford, L. V.: Possible evidence of flux transfer events in the polar ionosphere, Geophys. Res. Lett., 11, 1089–1092, 1986.

Lepping, R. P., Acuña, M. H., Burlaga, L. F., Farrell, W. M., Slavin, J. A., Schatten, K. H., Mariani. F., Ness, N. F., Meubauer, F. M., Whang, Y. C., Byrnes, J. B., Kennon, R. S., Panetta, P. V., Scheifele, J., and Morley, E. M.: The Wind magnetic field investigation, Space Sci. Rev., 71, 207–229, 1995.

Lockwood, M.: Relationship of dayside auroral precipitations to the open-closed separatrix and patterns of convective flow, J. Geophys. Res., 102, 17 475–17 487, 1997.

Maynard, N. C.: Svalbard: A window for understanding temporal/spatial aspects of solar wind coupling to the magnetosphere and ionosphere, in: Egeland Symposium on Auroral and Atmospheric Research, edited by: Moen, J. and Holtet, J. A., p. 75–89, Department of Physics, University of Oslo, ISBN 82-91853-09-6, 2003.

Maynard, N. C.: Coupling the solar-wind/IMF to the ionosphere through the high latitude cusps, Surveys in Geophysics, 26, 255–280, https://doi.org/10.1007/s10712-005-1882-4, 2005.

Maynard, N. C., Burke, W. J., Pfaff, R. F., Weber, E. J., Ober, D. M., Weimer, D. R., Moen, J., Milan, S., Sandholt, P. E., Egeland, A., Søraas. F., Lepping, R., Bounds, S., Acuña, M. H., Freudenreich, H., Gentile, L. C., Hardy, D. A., Holtet, J. A., Lester, M., Machuzak, J. S., Clemmons, J. H., Ning, P., Stadsnes, J., and van Eyken, T.: Driving dayside convection with northward IMF: Observations of a sounding rocket from Svalbard, J. Geophys. Res., 105, 5245–5263, 2000.

Maynard, N. C., Savin, S., Erickson, G. M., Kawano, H., N\veme\vcek, Z., Peterson, W. K., \vSafránoková, J., Sandahl, I., Scudder, J. D., Siscoe, G. L., Sonnerup, B. U. Ö., Weimer, D. R., White, W. W., and Wilson, G. R.: Observation of the magnetospheric "sash" and its implications relative to solar-wind/magnetosphere coupling: A multisatellite event analysis, J. Geophys. Res., 106, 6097–6122, 2001a.

Maynard, N. C., Burke, W. J., Sandholt, P. E., Moen, J., Ober, D. M., Lester, M., Weimer, D. R., and Egeland, A.: Observations of simultaneous effects of merging in both hemispheres, J. Geophys. Res., 106, 24 551–24 577, 2001b.

Maynard, N. C., Ober, D. M., Burke, W. J., Scudder, J. D., Lester, M., Dunlop, M., Wild, J. A., Grocott, A., Farrugia, C. J., Lund, E. J., Russell, C. T., Weimer, D. R., Siebert, K. D., Balogh, A., Andre, M., and Rème, H.: Polar, Cluster and SuperDARN evidence for high latitude merging during southward IMF: temporal/spatial evolution, Ann. Geophys., 21, 2233–2258, 2003.

Maynard, N. C., Moen, J., Burke, W. J., Lester, M., Ober, D. M., Scudder, J. D., Siebert, K. D., Weimer, D. R., Russell, C. T., and Balogh, A.: Temporal-spatial structure of magnetic merging at the magnetopause inferred from 557.7-nm all-sky images, Ann. Geophys., 22, 2917–2942, 2004.

Maynard, N. C., Burke, W. J., Scudder, J. D., Ober, D. M., Weimer, D. R., Siebert, K. D., Russell, C. T., Lester, M., Mozer, F. S., and Sato, N.: Electron signatures of active merging sites on the magnetopause, J. Geophys. Res., 110, A10207, https://doi.org/10.1029/2004JA010639, 2005.

McComas, D. J., Bame, S. J., Barber, P., Fieldman, W. C., Phillips, J. L., and Riley, P.: Solar wind electron, proton, and alpha monitor (SWEPAM) on the Advanced Composition Explorer, Space Sci. Rev., 86, 563–612, 1998.

Moore, T. E., Fok, M.-C., and Chandler, M. O.: The dayside reconnection X-line, J. Geophys. Res., 107(A10), 1332, https://doi.org/10.1029/2002JA009381, 2002.

Newell, P. T. and Meng, C. I.: Ionospheric projection of magnetospheric regions under low and high solar wind pressure conditions, J. Geophys. Res., 99, 273–286, 1994.

Ober, D. M., Maynard, N. C., Burke, W. J., Moen, J., Egeland, A., Sandholt, P. E., Farrugia, C. J., Weber, E. J., and Scudder, J. D.: Mapping prenoon auroral structures to the magnetosphere, J. Geophys. Res., 105, 27 519–27 530, 2000.

Ogilvie, K. W., Fitzenreiter, R. J., and Scudder, J. D.: Observations of electron beams in the low latitude boundary layer, J. Geophys. Res., 89, 10 723–10 732, 1984.

Ogilvie, K. W., Chornay, D. J., Fitzenreiter, 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.

Rees, M. H.: Auroral ionization and excitation by incident energetic electrons, Planet. Space Sci., 11, 1209–1218, 1963.

Rème, H., Aoustin, C., Bosqued, J. M., Dandouras, I., et al.: First multispacecraft ion measurements in and near the Earth's magnetosphere with the identical Cluster Ion Spectrometry (CIS) experiment, Ann. Geophys., 19, 1303–1354, 2001.

Roger, A. S., Chisham, G., Coleman, I. J., Freeman, M. P., and Pinnock, M.: Anti-parallel reconnection at the dayside magnetopause: Ionospheric signatures and implications for the low latitude boundary layer, in: Earth's Low-Latitude Boundary Layer, Geophysical Monograph 133, edited by: Newell, P. T. and Onsager, T., pp. 311–318, American Geophysical Union, 2003.

Sandholt, P. E. and Farrugia, C. J.: Monitoring magnetosheath-magnetosphere interconnection topology from the aurora, Ann. Geophys., 20, 629–637, 2002.

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

Sandholt, P. E., Farrugia, C. J., Burlaga, L. F., Holtet, J. A., Moen, J., Lybekk, B., Jacobsen, B., Opsvik, D., Egeland, A., Lepping, R., Lazarus, A. J., Hansen, T., Brekke, A., and Friis-Christensen, E.: Cusp/cleft auroral activity in relation to solar wind dynamic pressure, IMF $B_Z$ and $B_Y$, in: Physical Signatures of Magnetospheric Boundary Layer Processes, edited by: Holtet, J. A. and Egeland, A., pp. 173–188, Kluwer Academic Pub., Dordrecht, 1994.

Sandholt, P. E., Farrugia, C. J., Moen, J., Noraberg, Ø., Lybekk, B., Sten, T., and Hansen, T.: A classification of dayside auroral forms and activities as a function of interplanetary magnetic field orientation, J. Geophys. Res., 103, 23 325–23 345, 1998.

Sandholt, P. E., Denig, W. F., Farrugia, C. J., Lybekk, B., and Trondsen, E.: Auroral structure at the cusp equatorward boundary: relationship with the electron edge of the low latitude boundary layer precipitation, J. Geophys. Res., 107(A9), 1235, https://doi.org/10.1029/2001JA00581, 2002.

Sandholt, P. E., Farrugia, C. J., and Denig, W. F.: Dayside aurora and the role of IMF $|B_Y|/|B_Z|$: detailed morphology and response to magnetopause reconnection, Ann. Geophys. 22, 613–628, 2004.

Sanny, J., Sibeck, D. G., Venturinni, C. C., and Russell, C. T.: A statistical study of transient events in the outer dayside magnetosphere, J. Geophys. Res., 101, 4939–4952, 1996.

Schwartz, S. J., Paschmann, G., Sckopke, N., Bauer, T. M., Dunlop, M., Fazakerley, A. N., and Thomsen, M. F.: Conditions for the formation of hot flow anomalies at Earth's bow shock, J. Geophys. Res., 105, 12 639–12 650, 2000.

Scudder, J. D., Mozer, F. S., Maynard, N. C., and Russell, C. T.: Fingerprints of collisionless reconnection at the separator: Ambipolar-Hall signatures, J. Geophys. Res., 107(A10), https://doi.org/10.1029/2001JA000126, 2002.

Sibeck, D. G.: A model for the transient magnetospheric response to sudden solar wind dynamic pressure variations, J. Geophys. Res., 95, 3755–3771, 1990.

Sibeck, D. G., Trivedi, N. B., Zesta, E., Decker, R. B., Singer, H. J., Szabo, A., Tachihara, H., and Watermann, J.: Pressure pulse interaction with the magnetosphere and ionosphere, J. Geophys. Res. 108(A2), 1095, https://doi.org/10.1029/2002JA009675, 2003.

Siscoe, G., Crooker, N., Siebert, K., Maynard, N., Weimer, D., and White, W.: Cusp geometry in MHD simulation, Surveys in Geophysics, 26, 387–407, https://doi.org/10.1007/s10712-005-1902-4, 2005.

Smith, C. W., Acuña, M. H., Burlaga, L. F., L'Heureux, J., Ness, N. F., and Scheifele, J.: The ACE Magnetic Field Experiment, Space Sci. Rev., 86, 613–632, 1998.

Sonnerup, B. U. Ö.: Magnetopause reconnection rate, J. Geophys. Res. 79, 1546–1549, 1974.

Sonnerup, B. U. Ö., Paschmann, G., Papamastorakis, I., Sckopke, N., Haerendel, G., Bame, S. J., Asbridge, J. R., Gosling, J. T., and Russell, C. T.: Evidence for magnetic reconnection at the earth's magnetopause, J. Geophys. Res., 86, 10 049–10 067, 1981.

Southward, D. J. and Kivelson, M. G.: The magnetohydrodynamic response to the magnetospheric cavity to changes in solar wind dynamic pressure, J. Geophys. Res., 95, 2301–2309, 1990.

Vaisberg, O. L., Smirnov, V. N., Avanov, L. A., Waite Jr., J. H., Burch, J. L., Gallagher, D. L., and Borodkova, N. L.: Different types of low-latitude boundary layer observed by Interball-Tail probe, J. Geophys. Res., 106, 13 067–13 090, 2001.

Weimer, D. R., Ober, D., Maynard, N. C., Burke, W. J., Collier, M. R., McComas, D. J., Ness, N. F., and Smith, C. W.: Variable time delays in the propagation of the interplanetary magnetic field, J. Geophys. Res., 107(A8), https://doi.org/10.1029/2001JA009102, 2002.

White, W. W., Siscoe, G. L., Erickson, G. M., Kaymaz, Z., Maynard, N. C., Siebert, K. D., Sonnerup, B. U. Ö., and Weimer, D. R.: The magnetospheric sash and cross-tail S, Geophys. Res. Lett., 25, 1605–1608, 1998.

White, W. W., Schoendorf, J. A., Siebert, K. D., Maynard, N. C., Weimer, D. R., Wilson, G. L., Sonnerup, B. U. Ö., Siscoe, G. L., and Erickson, G. M.: MHD simulation of magnetospheric transport at the mesoscale, in: Space Weather, Geophysical Monograph Series Vol. 125, edited by: Song, P., Singer, H. J., and Siscoe, G. L., pp. 229–240, American Geophys. Union, 2001.

Zesta, E., Hughes, W. J., Engebretson, M. J., Hughes, T. J., Lazarus, A. J., and Paulerina, K. I.: The November 9, 1993, traveling convection vortex event: A case study, J. Geophys. Res., 104, 28 041–28 058, 1999.