Coronal hole

  • Coronal Hole
  • An extended region of the corona, exceptionally low in density and associated with unipolar photospheric regions. A coronal hole can be an "open" magnetic field in the corona and (perhaps) inner heliosphere which has a faster than average outflow (wind); A region of lower than "quiet" ion and electron density in the corona; or a region of lower peak electron temperature in the corona than in the "quiet" corona.
Abstract from DBPedia
    Coronal holes are areas where the Sun's corona is colder, hence darker, and has lower-density plasma than average because there is lower energy and gas levels. Coronal holes are part of the Sun's corona and are constantly changing and reshaping because the corona is not uniform. The Sun contains magnetic fields that arch away from areas in the corona that are very thin due to the lower levels of energy and gas, which cause coronal holes to appear when they do not fall back. Thus, solar particles escape at a rate great enough to create a lower density and lower temperature in that area.

    コロナホール(Coronal hole)は、太陽のコロナが平均よりも暗く、冷たく、密度が低い領域である。コロナの構造の解明のために地球の大気外に打ち上げられたスカイラブ計画のX線望遠鏡によって発見された。コロナホールは、開いた磁力線が密集した単極に繋がっている。太陽活動の極小期には、コロナホールは主に極地方で見られるが、極大期にはどこにでも存在しうる。太陽風の速い成分は、開いた磁力線に沿って移動し、コロナホールを通ることが知られている。