Outflow velocity of interplume regions at the base of Polar Coronal Holes

TitleOutflow velocity of interplume regions at the base of Polar Coronal Holes
Publication TypeJournal Article
Year of Publication2000
AuthorsPatsourakos, S., and Vial J.-C.
JournalAstronomy and Astrophysics
Volume359
PaginationL1-L4
Date PublishedJul
Abstract

We report on SUMER/SOHO observations at 1.05 R$_{sun}$ of a well identified interplume region in a South Pole Coronal Hole. Combination of Doppler shifts and Doppler dimming measurements allowed to determine, for the first time, the total wind outflow velocity (\~ 67 km s$^{-1}$) at this height. Our calculations of the outflow velocity benefit from co-spatial and almost co-temporal observations. This large outflow velocity is a strong argument in favour of the interplumes being the main source of the fast solar wind. We find that the mass flux density through the observed interplume is 4.8 10$^{-10}$ g cm$^{-2}$s$^{-1}$ which yields 10$^{-15}$ g cm$^{-2}$s$^{-1}$ at 1 AU with an expansion factor of 11.