The Origin of Sunspot: Exploration by Local and Global MHD Numerical Models

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K17611
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Astronomy
• Research Institution: Aichi University of Education
• Principal Investigator: MASADA YOUHEI 愛知教育大学, 教育学部, 講師 (30590608)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 太陽 / ダイナモ / 電磁流体力学 / 天文学 / 流体力学

Outline of Final Research Achievements

A longstanding goal of solar interior physics is to self-consistently reproduce sunspots from magnetic fluxes generated in the solar interior. However, there is still a large gap between the dynamo theory in the interior and the active region formation theory at the surface. For bridging the gap between them, we conducted in this study a convective dynamo simulation in a strongly stratified atmosphere resembling the solar interior in Cartesian geometry. In addition to the large-scale dynamo which has physical properties similar to those in earlier weakly-stratified convective dynamo simulations (Masada & Sano 2014a,b), we found that large-scale structures of the vertical magnetic field are spontaneously organized in the convection zone surface only in cases with a strongly-stratified atmosphere (Masada & Sano 2016, ApJL). Additionally, we found the critical Rossby-number for successful large-scale dynamo is around Ro = 0.03 (Masada & Sano 2018 in prep.).

Free Research Field

天体物理学