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

TL;DR

This study combines Ca II K spectro-heliograms and Hinode data to observe the detailed dynamics and evolution of magnetic flux emergence from the photosphere to the chromosphere, confirming simulation predictions.

Contribution

First observational confirmation of the gradual rising phase of weak magnetic flux tubes from photosphere to chromosphere using combined spectroscopic and satellite data.

Findings

Emerging flux detected first in photospheric magnetic signals.

Horizontal expansion observed 3 minutes after initial detection.

Emerging loops reached up to 2.1 km/s rise speed at chromospheric heights.

Abstract

A cooperative observation with Hida observatory and Hinode satellite was performed on an emerging flux region. The 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 Fe I Stokes IQUV filtergrams. In this study, detailed dynamics and temporal evolution of the magnetic flux emergence was studied observationally. The event was first detected in the photospheric magnetic field signals. 3 minutes later, the horizontal expansion of the dark area was detected. And then, 7 minutes later than the horizontal expansion, the emerging loops were detected with the maximal rise speed of 2.1 km/s at chromospheric heights. The observed dynamics of emerging magnetic flux from the photosphere to the upper chromosphere is well consistent with the results of previous simulation works. The gradual rising phase of flux tubes with a weak magnetic strength was confirmed by our observation.