Ca II K Spectral Study of an Emerging Flux Region using the Domeless Solar Telescope in Hida Observatory

Abstract

A cooperative observation with Hida Observatory and the Hinode satellite was performed on an emerging flux region. Successive Ca II K spectro-heliograms of the emerging flux region were taken by the Domeless Solar Telescope of Hida Observatory. Hinode observed the emerging flux region with Ca II H and FeI Stokes IQUV filtergrams. In this study, detailed dynamics and the temporal evolution of the magnetic flux emergence was studied observationally. The event was first detected in the photospheric magnetic field signals; 3 minutes later, a horizontal expansion of the dark area was detected. Then, 7 minutes later than the horizontal expansion, the emerging loops were detected with a maximal rise speed of 2.1 km s$^{-1}$ at chromospheric heights. The observed dynamics of the emerging magnetic flux from the photosphere to the upper chromosphere was very consistent with the results of previous simulation studies. A gradual rising phase of flux tubes with a weak magnetic strength was confirmed by our observation.