Advertisement

Solar Physics

, Volume 267, Issue 1, pp 175–202 | Cite as

Examining Periodic Solar-Wind Density Structures Observed in the SECCHI Heliospheric Imagers

  • Nicholeen M. Viall
  • Harlan E. Spence
  • Angelos Vourlidas
  • Russell Howard
Article

Abstract

We present an analysis of small-scale, periodic, solar-wind density enhancements (length scales as small as ≈ 1000 Mm) observed in images from the Heliospheric Imager (HI) aboard STEREO-A. We discuss their possible relationship to periodic fluctuations of the proton density that have been identified at 1 AU using in-situ plasma measurements. Specifically, Viall, Kepko, and Spence (J. Geophys. Res. 113, A07101, 2008) examined 11 years of in-situ solar-wind density measurements at 1 AU and demonstrated that not only turbulent structures, but also nonturbulent, periodic density structures exist in the solar wind with scale sizes of hundreds to one thousand Mm. In a subsequent paper, Viall, Spence, and Kasper (Geophys. Res. Lett. 36, L23102, 2009) analyzed the α-to-proton solar-wind abundance ratio measured during one such event of periodic density structures, demonstrating that the plasma behavior was highly suggestive that either temporally or spatially varying coronal source plasma created those density structures. Large periodic density structures observed at 1 AU, which were generated in the corona, can be observable in coronal and heliospheric white-light images if they possess sufficiently high density contrast. Indeed, we identify such periodic density structures as they enter the HI field of view and follow them as they advect with the solar wind through the images. The smaller, periodic density structures that we identify in the images are comparable in size to the larger structures analyzed in-situ at 1 AU, yielding further evidence that periodic density enhancements are a consequence of coronal activity as the solar wind is formed.

Keywords

Solar Wind Density Structure Slow Solar Wind Density Enhancement Heliospheric Imager 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Supplementary material

(AVI 4.04MB)

(AVI 11.2MB)

References

  1. Billings, D.E.: 1966, A Guide to the Solar Corona, Academic Press, New York. Google Scholar
  2. Harrison, R.A., Davis, C.J., Eyles, C.J., Bewsher, D., Crothers, S., Davies, J.A., Howard, R.A., Moses, D.J., Socker, D.G., Halain, J.-P., Defise, J.-M., Mazy, E., Rochus, P., Webb, D.F., Simnett, G.M.: 2008, Solar Phys. 247, 171. CrossRefADSGoogle Scholar
  3. Harrison, R.A., Davies, J.A., Rouillard, A.P., Davis, C.J., Eyles, C.J., Bewsher, D., Crothers, S.R., Howard, R.A., Sheeley, N.R., Vourlidas, A., Webb, D.F., Brown, D.S., Dorrian, G.D.: 2009, Solar Phys. 256, 219. CrossRefADSGoogle Scholar
  4. Howard, R.A., Moses, J.D., Vourlidas, A., Newmark, J.S., Socker, D.G., Plunkett, S.P., Korendyke, C.M., Cook, J.W., Hurley, A., Davila, J.M., et al.: 2008, Space Sci. Rev. 136, 67. CrossRefADSGoogle Scholar
  5. Kaiser, M.L., Kucera, T.A., Davila, J.M., St. Cyr, O.C., Guhathakurta, M., Christian, E.: 2008, Space Sci. Rev. 136, 5. CrossRefADSGoogle Scholar
  6. Kepko, L., Spence, H.E.: 2003, J. Geophys. Res. 108, 1257. CrossRefGoogle Scholar
  7. Kepko, L., Spence, H.E., Singer, H.J.: 2002, Geophys. Res. Lett. 29, 080000. CrossRefGoogle Scholar
  8. Mann, M., Lees, J.M.: 1996, Clim. Change 33, 409. CrossRefGoogle Scholar
  9. Rouillard, A.P., Savani, N.P., Davies, J.A., Lavraud, B., Forsyth, R.J., Morley, S.K., Opitz, A., Sheeley, N.R., Burlaga, L.F., Sauvaud, J.-A., Simunac, K.D.C., Luhmann, J.G., Galvin, A.B., Crothers, S.R., Davis, C.J., Harrison, R.A., Lockwood, M., Eyles, C.J., Bewsher, D., Brown, D.S.: 2009, Solar Phys. 256, 307. CrossRefADSGoogle Scholar
  10. Rouillard, A.P., Davies, J.A., Lavraud, B., Forsyth, R.J., Savani, N.P., Bewsher, D., Brown, D.S., Sheeley, N.R., Davis, C.J., Harrison, R.A., Howard, R.A., Vourlidas, A., Lockwood, M., Crothers, S.R., Eyles, C.J.: 2010a, J. Geophys. Res. 115, 4103. CrossRefGoogle Scholar
  11. Rouillard, A.P., Lavraud, B., Davies, J.A., Savani, N.P., Burlaga, L.F., Forsyth, R.J., Sauvaud, J.-A., Opitz, A., Lockwood, M., Luhmann, J.G., Simunac, K.D.C., Galvin, A.B., Davis, C.J., Harrison, R.A.: 2010b, J. Geophys. Res. 115, 4104. CrossRefGoogle Scholar
  12. Sheeley, N.R. Jr., Warren, H.P., Wang, Y.-M.: 2007, Astrophys. J. 671, 926. CrossRefADSGoogle Scholar
  13. Sheeley, N.R. Jr., Wang, Y., Hawley, S.H., Brueckner, G.E., Dere, K.P., Howard, R.A., Koomen, M.J., Korendyke, C.M., Michels, D.J., Paswaters, S.E., Socker, D.G., St. Cyr, O.C., Wang, D., Lamy, P.L., Llebaria, A., Schwenn, R., Simnett, G.M., Plunkett, S., Biesecker, D.A.: 1997, Astrophys. J. 484, 472. CrossRefADSGoogle Scholar
  14. Sheeley, N.R. Jr., Lee, D.D.-H., Casto, K.P., Wang, Y.-M., Rich, N.B.: 2009, Astrophys. J. 694, 1471. CrossRefADSGoogle Scholar
  15. Stephenson, J.A.E., Walker, A.D.M.: 2002, Geophys. Res. Lett. 29(9), 1297. doi: 10.1029/2001GL014291. CrossRefADSGoogle Scholar
  16. Thomson, D.J.: 1982, IEEE 70, 1055. CrossRefADSGoogle Scholar
  17. Viall, N.M., Kepko, L., Spence, H.E.: 2008, J. Geophys. Res. 113, A07101. doi: 10.1029/2007JA012881. CrossRefGoogle Scholar
  18. Viall, N.M., Kepko, L., Spence, H.E.: 2009, J. Geophys. Res. 114, A01201. doi: 10.1029/2008JA013334. CrossRefGoogle Scholar
  19. Viall, N.M., Spence, H.E., Kasper, J.: 2009, Geophys. Res. Lett. 36, L23102. doi: 10.1029/2009GL041191. CrossRefADSGoogle Scholar
  20. Vourlidas, A., Howard, R.A.: 2006, Astrophys. J. 642, 1216. CrossRefADSGoogle Scholar
  21. Wang, Y.-M., Sheeley, N.R. Jr., Walters, J.H., Brueckner, G.E., Howard, R.A., Michels, D.J., Lamy, P.L., Schwenn, R., Simnett, G.M.: 1998, Astrophys. J. Lett. 498, L165. CrossRefADSGoogle Scholar
  22. Wang, Y.-M., Sheeley, N.R. Jr., Socker, D.G., Howard, R.A., Rich, N.B.: 2000, J. Geophys. Res. 105, A11. Google Scholar

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • Nicholeen M. Viall
    • 1
  • Harlan E. Spence
    • 2
  • Angelos Vourlidas
    • 3
  • Russell Howard
    • 3
  1. 1.Solar Physics LabNASA Goddard Space Flight CenterGreenbeltUSA
  2. 2.Space Science CenterUniversity of New HampshireDurhamUSA
  3. 3.Solar Physics BranchNaval Research LaboratoryWashingtonUSA

Personalised recommendations