Slow Solar Wind: Origin in an Independent Small-Scale Solar Dynamo

Abstract

Separation of the solar wind (SW) into three flow types (coronal mass ejections (CMEs), high speed streams (HSSs), and slow solar wind (SSW)) reveals an inverse relationship between the percentage of time Earth spends in SSW during a year and its annually averaged magnetic field strength (B). This relationship maintains a quasi-constant floor of ∼2.8 nT in SW B carried to the heliosphere by the SSW during the last ∼60 years, in contrast to the contributions of CMEs and HSSs to SW B that exhibit the 11-year variation of the large-scale (LS) dynamo. We propose the SSW is not a by-product of the LS-dynamo, as currently thought, but rather results from a small-scale dynamo that continually replenishes intranetwork flux that undergoes flux cancellation reconnection, to supply a fixed amount of open flux to the heliosphere. Of the three SW flow types, only SSW appears to be spatially/temporally ubiquitous.