Solar Physics

, Volume 256, Issue 1, pp 307–326

A Multispacecraft Analysis of a Small-Scale Transient Entrained by Solar Wind Streams

  • A. P. Rouillard
  • N. P. Savani
  • J. A. Davies
  • B. Lavraud
  • R. J. Forsyth
  • S. K. Morley
  • A. Opitz
  • N. R. Sheeley
  • L. F. Burlaga
  • J.-A. Sauvaud
  • K. D. C. Simunac
  • J. G. Luhmann
  • A. B. Galvin
  • S. R. Crothers
  • C. J. Davis
  • R. A. Harrison
  • M. Lockwood
  • C. J. Eyles
  • D. Bewsher
  • D. S. Brown
Open Access
STEREO SCIENCE RESULTS AT SOLAR MINIMUM

DOI: 10.1007/s11207-009-9329-6

Cite this article as:
Rouillard, A.P., Savani, N.P., Davies, J.A. et al. Sol Phys (2009) 256: 307. doi:10.1007/s11207-009-9329-6

Abstract

The images taken by the Heliospheric Imagers (HIs), part of the SECCHI imaging package onboard the pair of STEREO spacecraft, provide information on the radial and latitudinal evolution of the plasma compressed inside corotating interaction regions (CIRs). A plasma density wave imaged by the HI instrument onboard STEREO-B was found to propagate towards STEREO-A, enabling a comparison between simultaneous remote-sensing and in situ observations of its structure to be performed. In situ measurements made by STEREO-A show that the plasma density wave is associated with the passage of a CIR. The magnetic field compressed after the CIR stream interface (SI) is found to have a planar distribution. Minimum variance analysis of the magnetic field vectors shows that the SI is inclined at 54° to the orbital plane of the STEREO-A spacecraft. This inclination of the CIR SI is comparable to the inclination of the associated plasma density wave observed by HI. A small-scale magnetic cloud with a flux rope topology and radial extent of 0.08 AU is also embedded prior to the SI. The pitch-angle distribution of suprathermal electrons measured by the STEREO-A SWEA instrument shows that an open magnetic field topology in the cloud replaced the heliospheric current sheet locally. These observations confirm that HI observes CIRs in difference images when a small-scale transient is caught up in the compression region.

Keywords

Sun: magnetic field Sun: corotating interaction regions Interplanetary medium: coronal mass ejection 
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Copyright information

© The Author(s) 2009

Authors and Affiliations

  • A. P. Rouillard
    • 1
    • 2
  • N. P. Savani
    • 3
  • J. A. Davies
    • 2
  • B. Lavraud
    • 4
    • 5
  • R. J. Forsyth
    • 3
  • S. K. Morley
    • 6
  • A. Opitz
    • 4
    • 5
  • N. R. Sheeley
    • 7
  • L. F. Burlaga
    • 8
  • J.-A. Sauvaud
    • 4
    • 5
  • K. D. C. Simunac
    • 9
  • J. G. Luhmann
    • 10
  • A. B. Galvin
    • 9
  • S. R. Crothers
    • 2
  • C. J. Davis
    • 2
  • R. A. Harrison
    • 2
  • M. Lockwood
    • 1
    • 2
  • C. J. Eyles
    • 11
    • 2
  • D. Bewsher
    • 12
    • 2
  • D. S. Brown
    • 12
  1. 1.Space Environment Physics Group, School of Physics and AstronomyUniversity of SouthamptonSouthamptonUK
  2. 2.Space Science and Technology DepartmentRutherford Appleton LaboratoryChiltonUK
  3. 3.Space and Atmospheric Physics, Blackett LaboratoryImperial College LondonLondonUK
  4. 4.Centre d’Etude Spatiale des RayonnementsUniversité de Toulouse (UPS)ToulouseFrance
  5. 5.Centre National de la Recherche ScientifiqueToulouseFrance
  6. 6.Centre for Space PhysicsUniversity of NewcastleNewcastleAustralia
  7. 7.Space Science DivisionNaval Research LaboratoryWashingtonUSA
  8. 8.Goddard Space Flight CenterNASA/GSFCGreenbeltUSA
  9. 9.Institute for the Study of Earth Oceans and SpaceUniversity of New HampshireDurhamUSA
  10. 10.Space Science LaboratoryUniversity of CaliforniaBerkeleyUSA
  11. 11.Grupo de Astronomia y Ciencias del EspacioUniversidad de ValenciaValenciaSpain
  12. 12.Institute of Mathematical and Physical SciencesUniversity of Wales AberystwythAberystwythUK

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