An observation of solar active region expansion into the heliosphere

Authors Organisations
Type Article
Original languageEnglish
Pages (from-to)L74-L78
Number of pages5
JournalMonthly Notices of the Royal Astronomical Society Letters
Issue number1
Publication statusPublished - 10 Jun 2013
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According to current models, solar closed-field active regions are isolated from contributing directly to the solar wind except through small- or large-scale magnetic reconnection, including coronal mass ejections. Here we show the first direct evidence of active regions contributing directly to the solar wind by a steady-state, quiescent expansion. Advanced image processing of coronagraph data reveals a large system of nested closed-field magnetic structures expanding and accelerating to heights of at least 14 R⊙ within a helmet streamer above a large active region. The system persists for several days, and must therefore be an important contribution to the slow solar wind.


  • Sun: corona, Sun: heliosphere, Sun: magnetic topology, solar wind