References

ANGEO

Annales Geophysicae

ANGEO

Ann. Geophys.

1432-0576

Copernicus Publications

Göttingen, Germany

10.5194/angeo-31-319-2013

Magnetosheath dynamic pressure enhancements: occurrence and typical properties

Archer

M. O.

https://orcid.org/0000-0003-1556-4573

¹ Horbury

T. S.

Space & Atmospheric Physics Group, The Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2BW, UK

26 02 2013

31 2 319 331

2013

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The first comprehensive statistical study of large-amplitude (> 100%) transient enhancements of the magnetosheath dynamic pressure reveals events of up to ~ 15 times the ambient dynamic pressure with durations up to 3 min and an average duration of around 30 s, predominantly downstream of the quasi-parallel shock. The dynamic pressure transients are most often dominated by velocity increases along with a small fractional increase in the density, though the velocity is generally only deflected by a few degrees. Superposed wavelet transforms of the magnetic field show that, whilst most enhancements exhibit changes in the magnetosheath magnetic field, the majority are not associated with changes in the Interplanetary Magnetic Field (IMF). However, there is a minority of enhancements that do appear to be associated with solar wind discontinuities which cannot be explained simply by random events. In general, it is found that during periods of magnetosheath dynamic pressure enhancements the IMF is steadier than usual. This suggests that a stable foreshock and hence foreshock structures or processes may be important in the generation of the majority of magnetosheath dynamic pressure enhancements.

References 1

Amata, E., Savin, S. P., Ambrosino, D., Bogdanova, Y. V., Marcucci, M. F., Romanov, S., and Skalsky, A.: High kinetic energy density jets in the {E}arth's magnetosheath: a case study, Planet. Space Sci., 59, 482–494, <a href="http://dx.doi.org/10.1016/j.pss.2010.07.021">https://doi.org/10.1016/j.pss.2010.07.021</a>, 2011.

Angelopoulos, V.: The THEMIS mission, Space Sci. Rev., 141, 5–34, <a href="http://dx.doi.org/10.1007/s11214-008-9336-1">https://doi.org/10.1007/s11214-008-9336-1</a>, 2008.

Archer, M. O., Horbury, T. S., and Eastwood, J. P.: Magnetosheath pressure pulses: generation downstream of the bow shock from solar wind discontinuities, J. Geophys. Res., 117, A05228, <a href="http://dx.doi.org/10.1029/2011JA017468">https://doi.org/10.1029/2011JA017468</a>, 2012.

Auster, H. U., Glassmeier, K. H., Magnes, W., Aydogar, O., Baumjohann, W., Constantinescu, D., Fischer, D., Fornacon, K. H., Georgescu, E., Harvey, P., Hillenmaier, O., Kroth, R., Ludlam, M., Narita, Y., Nakamura, R., Okrafka, K., Plaschke, F., Richter, I., Schwarzl, H., Stoll, B., Valavanoglou, A., and Wiedemann, M.: The THEMIS Fluxgate Magnetometer, Space Sci. Rev., 141, 235–264, <a href="http://dx.doi.org/10.1007/s11214-008-9365-9">https://doi.org/10.1007/s11214-008-9365-9</a>, 2008.

Cable, S., Lin, Y., and Holloway, J. L.: Intermediate shocks in three-dimensional magnetohydrodynamic bow-shock flows with multiple interacting shock fronts, J. Geophys. Res., 112, A09202, <a href="http://dx.doi.org/10.1029/2007JA012419">https://doi.org/10.1029/2007JA012419</a>, 2007.

Chen, S.-H., Kivelson, M. G., Gosling, J. T., Walker, R. J., and Lazarus, A. J.: Anomalous aspects of magnetosheath flow and of the shape and oscillations of the magnetopause during an interval of strongly northward interplanetary magnetic field, J. Geophys. Res., 98, 5727–5742, <a href="http://dx.doi.org/10.1029/92JA02263">https://doi.org/10.1029/92JA02263</a>, 1993.

Coleman, I. J.: A multi-spacecraft survey of magnetic field line draping in the dayside magnetosheath, Ann. Geophys., 23, 885–900, <a href="http://dx.doi.org/10.5194/angeo-23-885-2005">https://doi.org/10.5194/angeo-23-885-2005</a>, 2005.

Daum, P., Denton, M. H., Wild, J. A., Taylor, M. G. G. T., Šafránková, J., and Hayosh, M.: A general Cluster data and global MHD simulation comparison, Ann. Geophys., 26, 3411–3428, <a href="http://dx.doi.org/10.5194/angeo-26-3411-2008">https://doi.org/10.5194/angeo-26-3411-2008</a>, 2008.

De Sterck, H., Low, B. C., and Poedts, S.: Complex magnetohydrodynamic bow shock topology in field-aligned low-β flow around a perfectly conducting cylinder, Phys. Plasmas, 5, 4015–4027, <a href="http://dx.doi.org/10.1063/1.873124">https://doi.org/10.1063/1.873124</a>, 1998.

Dmitriev, A. V. and Suvorova, A. V.: Traveling magnetopause distortion related to a large-scale magnetosheath plasma jet: THEMIS and ground-based observations, J. Geophys. Res, 117, A08217, <a href="http://dx.doi.org/10.1029/2011JA016861">https://doi.org/10.1029/2011JA016861</a>, 2012.

Farris, M. H. and Russell, C. T.: Determining the standoff distance of the bow shock: {M}ach number dependence and use of models, J. Geophys. Res., 99, 17681–17689, <a href="http://dx.doi.org/10.1029/94JA01020">https://doi.org/10.1029/94JA01020</a>, 1994.

Farris, M. H., Petrinec, S. M., and Russell, C. T.: The thickness of the magnetosheath: Constraints on the polytropic index, Geophys. Res. Lett., 18, 1821–1824, <a href="http://dx.doi.org/10.1029/91GL02090">https://doi.org/10.1029/91GL02090</a>, 1991.

Gosling, J. T., Skoug, R. M., McComas, D. J., and Smith, C. W.: Direct evidence for magnetic reconnection in the solar wind near 1 AU, J. Geophys. Res., 110, A01107, <a href="http://dx.doi.org/10.1029/2004JA010809">https://doi.org/10.1029/2004JA010809</a>, 2005.

Hietala, H., Laitinen, T. V., Andréeová, K., Vainio, R., Vaivads, A., Palmroth, M., Pulkkinen, T. I., Koskinen, H. E. J., Lucek, E. A., and Rème, H.: Supermagnetosonic Jets behind a collisionless quasiparallel shock, Phys. Rev. Lett., 103, 245001, <a href="http://dx.doi.org/10.1103/PhysRevLett.103.245001">https://doi.org/10.1103/PhysRevLett.103.245001</a>, 2009.

Hietala, H., Partamies, N., Laitinen, T. V., Clausen, L. B. N., Facskó, G., Vaivads, A., Koskinen, H. E. J., Dandouras, I., Rème, H., and Lucek, E. A.: Supermagnetosonic subsolar magnetosheath jets and their effects: from the solar wind to the ionospheric convection, Ann. Geophys., 30, 33–48, <a href="http://dx.doi.org/10.5194/angeo-30-33-2012">https://doi.org/10.5194/angeo-30-33-2012</a>, 2012.

Kallio, E. J. and Koskinen, H. E. J.: A semiempirical magnetosheath model to analyze the solar wind-magnetosphere interaction, J. Geophys. Res., 105, 27469–27479, <a href="http://dx.doi.org/10.1029/2000JA900086">https://doi.org/10.1029/2000JA900086</a>, 2000.

Karlsson, T., Brenning, N., Trotignon, J.-G., Vallières, and Facskó, G.: Localized density enhancements in the magnetosheath: {T}hree-dimensional morphology and possible importance for impulsive penetration, J. Geophys. Res., 117, A03227, <a href="http://dx.doi.org/10.1029/2011JA017059">https://doi.org/10.1029/2011JA017059</a>, 2012.

Lavraud, B. and Borovsky, J. E.: Altered solar wind-magnetosphere interaction at low {M}ach numbers: {C}oronal mass ejections, J. Geophys. Res., 113, A00B08, <a href="http://dx.doi.org/10.1029/2008JA013192">https://doi.org/10.1029/2008JA013192</a>, 2008.

Lavraud, B., Borovsky, J. E., Ridley, A. J., Pogue, E. W., Thomsen, M. F., Rème, H., Fazakerly, A. N., and Lucek, E. A.: Strong bulk plasma acceleration in E}arth's magnetosheath: {A magnetic slingshot effect?, Geophys. Res. Lett., 34, L14102, <a href="http://dx.doi.org/10.1029/2007GL030024">https://doi.org/10.1029/2007GL030024</a>, 2007.

Le, G., Gosling, J. T., Russell, C. T., Elphic, R. C., Thomsen, M. F., and Newbury, J. A.: The magnetic and plasma structure of flux transfer events, J. Geophys. Res., 104, 233–245, <a href="http://dx.doi.org/10.1029/1998JA900023">https://doi.org/10.1029/1998JA900023</a>, 1999.

Lin, R., Anderson, K. A., Ashford, S., Carlson, C. W., Curtis, D., Ergun, R., Larson, D., McFadden, J. P., McCarthy, M., Parks, G. K., Rème, H. abd Bosqued, J. M., Coutelier, J., Cotin, F., D'Uston, C., Wenzel, K.-P., Sanderson, T. R., Henrion, J., Ronnet, J. C., and Paschmann, G.: A three-dimensional plasma and energetic particle investigation for the WIND spacecraft, Space Sci. Rev., 71, 125–153, <a href="http://dx.doi.org/10.1007/BF00751328">https://doi.org/10.1007/BF00751328</a>, 1995.

Lin, Y., Lee, L. C., and Yan, M.: Generation of dynamic pressure pulses downstream of the bow shock by variations in the interplanetary magnetic field orientation, J. Geophys. Res., 101, 479–493, <a href="http://dx.doi.org/10.1029/95JA02985">https://doi.org/10.1029/95JA02985</a>, 1996a.

Lin, Y., Swift, D. W., and Lee, L. C.: Simulation of pressure pulses in the bow shock and magnetosheath driven by variations in interplanetary magnetic field direction, J. Geophys. Res., 101, 27251–27269, <a href="http://dx.doi.org/10.1029/96JA02733">https://doi.org/10.1029/96JA02733</a>, 1996b.

Lucek, E. A., Constantinescu, D., Goldstein, M. L., Pickett, J., Pinçon, J. L., Sahraoui, F., Treumann, R. A., and Walker, S. N.: The Magnetosheath, Space Sci. Rev., 118, 95–152, <a href="http://dx.doi.org/10.1007/s11214-005-3825-2">https://doi.org/10.1007/s11214-005-3825-2</a>, 2005.

Luhmann, J. G., Russell, C. T., and Elphic, R. C.: Spatial distributions of magnetic field fluctuations in the dayside magnetosheath, J. Geophys. Res., 91, 1711–1715, <a href="http://dx.doi.org/10.1029/JA091iA02p01711">https://doi.org/10.1029/JA091iA02p01711</a>, 1986.

McFadden, J. P., Carlson, C. W., Larson, D., Ludlam, M., Abiad, R., Elliott, B., Turin, P., Marckwordt, M., and Angelopoulos, V.: The THEMIS {ESA} Plasma Instrument and In-flight Calibration, Space Sci. Rev., 141, 277–302, <a href="http://dx.doi.org/10.1007/s11214-008-9440-2">https://doi.org/10.1007/s11214-008-9440-2</a>, 2008a.

Němeček, Z., Šafránková, J., Přech, L., Sibeck, D. G., Kokubun, S., and Mukai, T.: Transient flux enhancements in the magnetosheath, Geophys. Res. Lett., 25, 1273, <a href="http://dx.doi.org/10.1029/98GL50873">https://doi.org/10.1029/98GL50873</a>, 1998.

Němeček, Z., Šafránková, J., Pišoft, P., and Zastenker, G. N.: Statistical study of ion flux fluctuations in the magnetosheath, Czech. J. Phys., 51, 853–862, <a href="http://dx.doi.org/10.1023/A:1011630618180">https://doi.org/10.1023/A:1011630618180</a>, 2001.

Paschmann, G., Sonnerup, B. U. ., Papamastorakis, I., Sckope, N., Haerendel, G., Bame, S. J., Asbridge, J. R., Gosling, J. T., Russell, C. T., and Elphic, R. C.: Plasma acceleration at the {E}arth's magnetopause: evidence for reconnection, Nature, 282, 243–246, <a href="http://dx.doi.org/10.1038/282243a0">https://doi.org/10.1038/282243a0</a>, 1979.

Phan, T. D., Paschmann, G., Twitty, C., Mozer, F. S., Gosling, J. T., Eastwood, J. P., Øieroset, M., Rème, H., and Lucek, E. A.: Evidence for magnetic reconnection initiated in the magnetosheath, Geophys. Res. Lett., 34, L14104, <a href="http://dx.doi.org/10.1029/2007GL030343">https://doi.org/10.1029/2007GL030343</a>, 2007.

Powell, K. G., Roe, P. L., Linde, T. J., Gombosi, T. I., and De Zeeuw, D. L.: A Solution-adaptive upwind scheme for Ideal Magnetohydrodynamics, J. Comput. Phys., 154, 284–309, <a href="http://dx.doi.org/10.1006/jcph.1999.6299">https://doi.org/10.1006/jcph.1999.6299</a>, 1999.

Russell, C. T. and Elphic, R. C.: Initial ISEE magnetometer results: {M}agnetopause observations, Space Sci. Rev., 22, 681–715, <a href="http://dx.doi.org/10.1007/BF00212619">https://doi.org/10.1007/BF00212619</a>, 1978.

Šafránková, J., Hayosh, M., Němeček, Z., and Přech, L.: Magnetosheath Investigations: I}nterball Contribution to the Topic, in: Multiscale processes in the {E}arth's magnetosphere: {F}rom {I}nterball to {C}luster, edited by: Sauvaud, J. A. and Němeček, Z., vol. 178 of {NATO science series, series {ii}: {m}athematics, physics and chemistry, pp. 73–94, Springer, 2004.

Savin, S., Amata, E., Zelenyi, L., Budaev, V., Consolini, G., Treumann, R., Lucek, E. A., Safrankova, J., Nemecek, Z., Khotyaintsev, Y., Andre, M., Buechner, J., Alleyne, H., Song, P., Blecki, J., Rauch, J. L., Romanov, S., Klimov, S., and Skalsky, A.: High energy jets in the {E}arth's magnetosheath: implications for plasma dynamics and anomalous transport, JETP Letters, 87, 593, <a href="http://dx.doi.org/10.1134/S0021364008110015">https://doi.org/10.1134/S0021364008110015</a>, 2008.

Savin, S., Budaev, V., Zelenyi, L., Amata, E., Sibeck, D., Lutsenko, V., Borodkova, N., Zhang, H., Angelopoulos, V., Safrankova, J., Nemecek, Z., Blecki, J., Buechner, J., Kozak, L., Romanov, S., Skalsky, A., and Krasnoselsky, W.: Anomalous Interaction of a Plasma Flow with the Boundary Layers of a Geomagnetic Trap, JETP Letters, 93, 754–762, <a href="http://dx.doi.org/10.1134/S0021364011120137">https://doi.org/10.1134/S0021364011120137</a>, 2011.

Savin, S., Amata, E., Zelenyi, L., Lutsenko, V., Safrankova, J., Nemecek, Z., Borodkova, N., Buechner, J., Daly, P. W., Kronberg, E. A., Blecki, J., Budaev, V., Kozak, L., Skalsky, A., and Lezhen, L.: Super fast plasma streams as drivers of transient and anomalous magnetospheric dynamics, Ann. Geophys., 30, 1–7, <a href="http://dx.doi.org/10.5194/angeo-30-1-2012">https://doi.org/10.5194/angeo-30-1-2012</a>, 2012.

Schwartz, S. J., Thomsen, M. F., Bame, S. J., and Stansberry, J.: Electron Heating and the Potential Jump Across Fast Mode Shocks, J. Geophys. Res., 93, 12923–12931, <a href="http://dx.doi.org/10.1029/JA093iA11p12923">https://doi.org/10.1029/JA093iA11p12923</a>, 1988.

Shue, J.-H., Song, P., Russell, C. T., Steinberg, J. T., Chao, J.-K., Zastenker, G., Vaisberg, O. L., Kokubun, S., Singer, H. J., Detman, T. R., and Kawano, H.: Magnetopause location under extreme solar wind conditions, J. Geophys. Res., 103, 17691–17700, <a href="http://dx.doi.org/10.1029/98JA01103">https://doi.org/10.1029/98JA01103</a>, 1998.

Shue, J.-H., Chao, J.-K., Song, P., McFadden, J. P., Suvorova, A., Angelopoulos, V., Glassmeier, K. H., and Plaschke, F.: Anomalous magnetosheath flows and distorted subsolar magnetopause for radial interplanetary magnetic fields, Geophys. Res. Lett., 36, L18112, <a href="http://dx.doi.org/10.1029/2009GL039842">https://doi.org/10.1029/2009GL039842</a>, 2009.

Smith, E. J.: Identification of interplanetary tangential and rotational discontinuities, J. Geophys. Res., 78, 2054–2063, <a href="http://dx.doi.org/10.1029/JA078i013p02054">https://doi.org/10.1029/JA078i013p02054</a>, 1973.

Smith, C. W., L'Heureux, J., Ness, N. F., Acuña, M. H., Burlaga, L. F., and Scheifele, J.: The ACE Magnetic fields experiment, Space Sci. Rev., 86, 613–632, <a href="http://dx.doi.org/10.1023/A:1005092216668">https://doi.org/10.1023/A:1005092216668</a>, 1998.

Torrence, C. and Compo, G. P.: A practical guide to wavelet analysis, B. Am. Meteorol. Soc., 79, 61–78, <a href="http://dx.doi.org/10.1175/1520-0477(1998)079<0061:APGTWA>2.0.CO;2">https://doi.org/10.1175/1520-0477(1998)079<0061:APGTWA>2.0.CO;2</a>, 1998.

Tsubouchi, K. and Matsumoto, H.: Effect of upstream rotational field on the formation of magnetic depressions in a quasi-perpendicular shock downstream, J. Geophys. Res., 110, A04101, <a href="http://dx.doi.org/10.1029/2004JA010818">https://doi.org/10.1029/2004JA010818</a>, 2005.

Vasquez, B. J., Abramenko, V. I., Haggerty, D. K., and Smith, C. W.: Numerous small magnetic field discontinuities of Bartels rotation 2286 and the potential role of Alfvénic turbulence, J. Geophys. Res., 112, A11102, <a href="http://dx.doi.org/10.1029/2007JA012504">https://doi.org/10.1029/2007JA012504</a>, 2007.

Walén, C.: On the theory of sunspots, Ark. Mat. Astron. Fys., 30A, 1–87, 1944.