Small Scale Magnetic Flux Emergence Observed with Hinode/Solar Optical Telescope
Abstract
We observed small scale magnetic flux emergence in a sunspot moat region by the Solar Optical Telescope (SOT) aboard the Hinode satellite. We analyzed filtergram images observed in the wavelengths of Fe 6302 angstrom, G-band and Ca II H. In Stokes I images of Fe 6302 angstrom, emerging magnetic flux were recognized as dark lanes. In G-band, they showed their shapes almost the same as in Stokes I images. These magnetic flux appeared as dark filaments in Ca II H images. Stokes V images of Fe 6302 angstrom showed pairs of opposite polarities at footpoints of each filament. These magnetic concentrations are identified to correspond to bright points in G-band/Ca II H images. From the analysis of time-sliced diagrams, we derived following properties of emerging flux, which are consistent with the previous works. (1) Two footpoints separate each other at a speed of 4.2 km/s during the initial phase of evolution and decreases to about 1 km/s in 10 minutes later. (2) Ca II H filaments appear almost simultaneously with the formation of dark lanes in Stokes I in the observational cadence of 2 minutes. (3) The lifetime of the dark lanes in Stokes I and G-band is 8 minutes, while that of Ca filament is 12 minutes. An interesting phenomena was observed that an emerging flux tube expands laterally in the photosphere with a speed of 3.8 km/s. Discussion on the horizontal expansion of flux tube will be given with refernce to previous simulation studies.
Keywords
Cite
@article{arxiv.0709.3207,
title = {Small Scale Magnetic Flux Emergence Observed with Hinode/Solar Optical Telescope},
author = {Kenichi Otsuji and Kazunari Shibata and Reizaburo Kitai and Satoru Ueno and Shin'ichi Nagata and Takuma Matsumoto and Tahei Nakamura and Hiroko Watanabe and Saku Tsuneta and Yoshinori Suematsu and Kiyoshi Ichimoto and Toshifumi Shimizu and Yukio Katsukawa and Theodore D. Tarbell and Bruce W. Lites and Richard A. Shine and Alan M. Title},
journal= {arXiv preprint arXiv:0709.3207},
year = {2015}
}
Comments
6 pages, 9 figures, accepted for publication in PASJ (Hinode Special Issue)