Chromospheric running wave from a solar cyclone produced through the emergence of a twisted magnetic flux tube

An innovative solar observing satellite, Hinode, has successfully observed the detailed evolution of an emerging magnetic field, starting from its appearance at the solar surface, to forming a developed bipolar region. The high spatial and temporal resolutions provided by the satellite has enabled us to capture prominent dynamic phenomena caused by the emerging magnetic field, such as a running wave in a chromospheric layer and the rotation of a magnetic polarity region on the Sun, which is reminiscent of a cyclone on Earth. A possible mechanism for producing the chromospheric running wave spreading from a solar cyclone has been demonstrated with a three-dimensional magnetohydrodynamic simulation for the emergence of a twisted flux tube. The simulation shows that as the emergence proceeds, an arc-shaped region with enhanced plasma density propagates outwards from the site of emergence.