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Evolution of coronal streamer structure during the rising phase of solar cycle 23
Author(s) -
Wang Y. M.,
Sheeley N. R.,
Rich N. B.
Publication year - 2000
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl010698
Subject(s) - physics , solar rotation , heliospheric current sheet , helmet streamer , sunspot , solar radius , current sheet , corona (planetary geology) , coronal hole , astronomy , heliosphere , coronal mass ejection , rotation (mathematics) , interplanetary magnetic field , plasma , solar wind , solar physics , magnetic field , magnetohydrodynamics , venus , geometry , nuclear physics , astrobiology , mathematics , quantum mechanics
White‐light images of the outer corona recorded with the Large Angle Spectrometric Coronagraph (LASCO) on the Solar and Heliospheric Observatory ( SOHO ) show a rapid widening of the streamer belt during 1998 and early 1999. The observed streamer structure and its evolution from rotation to rotation are reproduced with a model in which the Thomson‐scattering electrons are concentrated within a narrow layer centered around the heliospheric current sheet. The latitudinal spreading of the streamer belt is shown to be a consequence of the increased rate of magnetic flux emergence in the sunspot latitudes, which led to a weakening of the Sun's axisymmetric dipole moment, to a rapid growth in the nonaxisymmetric components of the coronal field, and hence to a strong tilting and warping of the plasma/current sheet.