Quiet Sun magnetic fields (1/2)                                     

Swedish 1-m Solar Telescope

This image shows a continuum intensity map of the solar granulation at disk center (left) and a longitudinal magnetogram of the same region constructed from the circular polarization observed in the red wing of the photospheric Fe I 617.3 nm spectral line (right). In the magnetogram, white represents fields pointing to the observer and black fields pointing away from the observer. The observations were taken with the CRISP instrument at the Swedish 1-m Solar Telescope on May 16, 2014. They are unprecedented in terms of magnetic sensitivity, as rather long exposure times were employed to reveal the weakest signals possible.

A comparison of the two panels shows that the stronger quiet Sun magnetic fields, both in network and internetwork regions, tend to be located in intergranular lanes. There, the converging horizontal flows of the adjacent granules become donwflows, producing a relatively stable environment for the fields to reside. In the intergranular lanes, the fields are organized on very small spatial scales and have mixed polarities everywhere. Observations show that granules also harbor magnetic fields, but they are much weaker and do not last long because the horizontal granular flows quickly expel them from the granular interior toward the adjacent integranular lanes.

Image credit: Luis Bellot Rubio (IAA-CSIC), Sara Esteban Pozuelo (IAA-CSIC), Ada Ortiz (ITA, University of Oslo)