JpGU-AGU Joint Meeting 2017

講演情報

[EE]Eveningポスター発表

セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM12] [EE] Space Weather, Space Climate, VarSITI

2017年5月23日(火) 17:15 〜 18:30 ポスター会場 (国際展示場 7ホール)

[PEM12-P09] Investigation of meridional flow pattern from mangetic elements motion

*Yusuke Iida1 (1.Kwansei Gakuin University)

キーワード:Sun, Magnetic Field, Surface Flow

Meridional flow, which is considered a persistent flow pattern along North-South direction, is important for solar dynamo problem. Despite its importance, observation of the meridional flow pattern is difficult because the amplitude is just ~10 m/s, which is just a few percent of that of convective flow pattern covering the solar surface. Hathaway and Lightmire (2010) succeeded in detecting the meridional flow pattern as an advection of magnetic region patterns between consecutive magnetograms obtained by SoHO/MDI. However, their study is limited to investigate the averaged pattern of magnetic region, not each magnetic element. Hence we try detecting the meridional flow pattern in the magnetic elements’ motion in this study, which is more direct detection and enable us to investigate deeper character of the flow.

North-south anisotropy in magnetic elements' motion is invetigated in the magnetograms obtained by Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamics Observatory (SDO). The magnetic elements are tracked by feature-tracking method of magnetic concentrations which is developed by the author. Our feature-tracking method and one-month magnetograms of SDO/HMI enable us to analyze huge number of magnetic elements’ motion. More than 5,000 elements are recegnized in one magnetogram with our detecting threshold and 108 displacements are obtained as total in our analysis. We found a small anisotropy along north-south direction and it shows similar latitudinal dependence obtained in Hathaway and Lightmire (2010), namely its amplitude increases up to ~14 m/s from the equator to ~60 degree in north and south hemisphere. Further we investigate the dependence of flow strength on magnetic elements character and newly found that larger elements have larger flow strength.