Helmet streamer

Helmet streamers during a total solar eclipse, photographed using exposure bracketing to show both the Sun's corona and the surface features of the new moon itself, illuminated by earthshine. A few solar prominences are visible around the lunar limb.

Helmet streamers, also known as coronal streamers, are elongated cusp-like structures in the Sun's corona which are often visible in white-light coronagraphs and during solar eclipses. They are closed magnetic loops which lie above divisions between regions of opposite magnetic polarity on the Sun's surface. The solar wind elongates these loops to pointed tips which can extend a solar radius or more into the corona.[1]

During solar minimum, helmet streamers are found closer to the heliographic equator, whereas during solar maximum they are found more symmetrically distributed around the Sun.

  1. ^ Kallenrode, May-Britt (2004). Space Physics: An Introduction to Plasmas and Particles in the Heliosphere and Magnetospheres. Berlin: Springer. p. 145. ISBN 3-540-20617-5.