政田 洋平

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アバター
研究者氏名
政田 洋平
 
マサダ ヨウヘイ
URL
http://www.phyas.aichi-edu.ac.jp/~ymasada/
所属
愛知教育大学
部署
教育学部 自然科学系
職名
准教授
学位
博士(京都大学)
ORCID ID
0000-0002-0767-3449

研究分野

 
 

経歴

 
2019年4月
 - 
現在
愛知教育大学 教育学部理科教育講座 准教授
 
2017年4月
 - 
2019年3月
愛知教育大学 教育学部理科教育講座 講師
 
2015年4月
 - 
2017年3月
愛知教育大学 現代学芸課程宇宙物質科学専攻 助教
 
2010年5月
 - 
2015年3月
神戸大学  大学院システム情報学研究科計算科学専攻 助教
 
2009年4月
 - 
2010年4月
自然科学研究機構国立天文台 太陽天体プラズマ研究部 研究員
 

学歴

 
2005年4月
 - 
2008年3月
京都大学 大学院理学研究科 物理学・宇宙物理学専攻
 
2003年4月
 - 
2005年3月
大阪大学 大学院理学研究科 宇宙地球科学専攻
 
1999年4月
 - 
2003年3月
大阪大学 理学部 物理学科
 

論文

 
Youhei Masada, Kei Kotake, Tomoya Takiwaki, Naoki Yamamoto
Phys. Rev. D 98, 083018 (2018)      2018年5月   [査読有り]
Macroscopic evolution of relativistic charged matter with chirality imbalance
is described by the chiral magnetohydrodynamics (chiral MHD). One such
astrophysical system is high-density lepton matter in core-collapse supernovae
where the chirality...
Bushby, P. J.; Käpylä, P. J.; Masada, Y.; Brandenburg, A.; Favier, B.; Guervilly, C.; Käpylä, M. J.
Astronomy & Astrophysics   612(A97) 16   2018年5月   [査読有り]
Context. Convectively driven flows play a crucial role in the dynamo processes that are responsible for producing magnetic activity in stars and planets. It is still not fully understood why many astrophysical magnetic fields have a significant la...
Katsukawa, Y.; Masada, Y.; Shimizu, T.; Sakai, S.; Ichimoto, K.
Proceedings of the SPIE, Volume 10565, id. 1056528 6 pp. (2017).      2017年11月
It is essential to achieve fine pointing stability in a space mission aiming for high resolutional observations. In a future Japanese solar mission SOLAR-C, which is a successor of the HINODE (SOLAR-B) mission, we set targets of angular resolution...
Youhei Masada, Takayoshi Sano
The Astrophysical Journal Letters, Volume 822, Issue 2, artivle id. L22, 7pp.      2016年4月   [査読有り]
We report the first successful simulation of spontaneous formation of surface
magnetic structures from a large-scale dynamo by strongly-stratified thermal
convection in Cartesian geometry. The large-scale dynamo observed in our
strongly-stratified...
Jun Mabuchi, Youhei Masada, Akira Kageyama
The Astrophysical Journal, Volume 806, Issue 1, article id. 10, 16 pp.      2015年4月   [査読有り]
Effects of magnetic field on stellar differential rotation are studied by
comparing magnetohydrodynamic (MHD) models and their hydrodynamic (HD)
counterparts in the broad range of rotation rate and in varying initial
rotation profile. Fully-compre...
Youhei Masada, Tomoya Takiwaki, Kei Kotake
The Astrophysical Journal Letters, Volume 798, Issue 1, article id. L22, 7 pp.      2014年11月   [査読有り]
Magnetorotational instability (MRI) in a convectively-stable layer around the
neutrinosphere is simulated by a three-dimensional model of supernova core. To
resolve MRI-unstable modes, a thin layer approximation considering only the
radial global ...
Youhei Masada, Takayoshi Sano
The Astrophysical Journal Letters, Volume 794, Issue 1, article id. L6, 5 pp      2014年9月   [査読有り]
The mechanism of large-scale dynamos in rigidly rotating stratified
convection is explored by direct numerical simulations (DNS) in Cartesian
geometry. A mean-field dynamo model is also constructed using turbulent
velocity profiles consistently ex...
Youhei Masada, Takayoshi Sano
Publications of the Astronomical Society of Japan, Volume 66, Issue SP1, id.S27 pp.      2014年3月   [査読有り]
Convective dynamo simulations are performed in local Cartesian geometry. We
report the first successful simulation of a large-scale oscillatory dynamo in
rigidly rotating convection without stably stratified layers. A key requirement
for exciting ...
Yuki YAMAURA, Youhei MASADA, Akira KAGEYAMA
Plasma and Fusion Research   8(1201135)    2013年9月   [査読有り]
A high-speed rendering method for three-dimensional animated volume rendering in a CAVE visualization environment is developed. The proposed method accelerates the standard three-dimensional texture-slicing approach to volume rendering by making u...
Jin Matsumoto, Youhei Masada
The Astrophysical Journal Letters, 772, L1      2013年6月   [査読有り]
We study the stability of a non-rotating single-component jet using
two-dimensional special relativistic hydrodynamic simulations. By assuming
translational invariance along the jet axis, we exclude the destabilization
effect by Kelvin-Helmholtz m...
Youhei Masada, Kohei Yamada, Akira Kageyama
The Astrophysical Journal, Volume 778, Issue 1, article id. 11, 14 pp.      2013年4月   [査読有り]
Spherical solar dynamo simulations are performed. Self-consistent, fully
compressible magnetohydrodynamic system with a stably stratified layer below
the convective envelope is numerically solved with a newly developed simulation
code based on the...
Akira Kageyama, Youhei Masada
Journal of Physics, Volume 454, Issue 1, article id. 012077      2013年1月   [査読有り]
We developed an application launcher called Multiverse for scientific
visualizations in a CAVE-type virtual reality (VR) system. Multiverse can be
regarded as a type of three-dimensional (3D) desktop environment. In
Multiverse, a user in a CAVE ro...
Masada, Youhei; Takiwaki, Tomoya; Kotake, Kei; Sano, Takayoshi
The Astrophysical Journal, Volume 759, Issue 2, article id. 110, 11 pp. (2012)   759(2)    2012年11月   [査読有り]
Bearing in mind the application of core-collapse supernovae, we study the nonlinear properties of the magnetorotational instability (MRI) by means of three-dimensional simulations in the framework of a local shearing box approximation. By systemat...
Jin Matsumoto, Youhei Masada, Kazunari Shibata
The Astrophysical Journal, Vol. 751, article id. 140,18pp.      2012年4月   [査読有り]
The effect of rarefaction acceleration on the propagation dynamics and
structure of relativistically hot jets is studied through relativistic
hydrodynamic simulations. We emphasize the nonlinear interaction of rarefaction
waves excited at the inte...
Kei Kotake, Tomoya Takiwaki, Yudai Suwa, Wakana Iwakami Nakano, Shio Kawagoe, Youhei Masada, Shin-ichiro Fujimoto
Advances in Astronomy, Vol.2012, id. 428757      2012年4月   [査読有り]
Core-collapse supernovae are dramatic explosions marking the catastrophic end
of massive stars. The only means to get direct information about the supernova
engine is from observations of neutrinos emitted by the forming neutron star,
and through ...
Meno, D., Kageyama, A., & Masada, Y
Transaction of the Japan Society for Simulation Technology,Vol.4, No4, pp190-193      2012年   [査読有り]
To analyze large scale 3-dimensional data, the modern virtual reality (VR) technology will play important roles in future simulation studies. Various VR visualization programs have been developed to date, including our original VR visualization so...
Hiroyuki R. Takahashi, Takahiro Kudoh, Youhei Masada, Jin Matsumoto
The Astrophysical Journal Letters,Vol.739, article id. L53, 5pp.      2011年8月   [査読有り]
Relativistic Sweet-Parker type magnetic reconnection is investigated by
relativistic resistive magnetohydrodynamic (RRMHD) simulations. As an initial
setting, we assume anti-parallel magnetic fields and a spatially uniform
resistivity. A perturbat...
Jin Matsumoto, Youhei Masada, Eiji Asano, Kazunari Shibata
The Astrophysical Journal, Vol. 733, article id. 18, 15pp      2011年3月   [査読有り]
The nonlinear dynamics of outflows driven by magnetic explosion on the
surface of a compact star is investigated through special relativistic
magnetohydrodynamic simulations. We adopt, as the initial equilibrium state, a
spherical stellar object e...
Hiroyuki R. Takahashi, Youhei Masada
The Astrophysical Journal, Vol. 727, article id. 106, 9pp      2010年11月   [査読有り]
Based on the characteristics of the magnetorotational instability (MRI) and
the MRI-driven turbulence, we construct a steady model for a geometrically thin
disk using "non-standard" Tex-prescription. The efficiency of the angular
momentum tra...
Youhei Masada
Monthly Notices of the Royal Astronomical Society: Letters (MNRAS Letters)   411 L26-L30   2010年11月   [査読有り]
The possible role of magneto-rotational instability (MRI) and its driven MHD
turbulence in the solar interior is studied on the basis of the linear and
nonlinear theories coupling with physical parameters, providing solar rotation
profile inverted...
Masada, Y., & Shibata, K
Revista Mexicana de Astronomia y Astrofísica, Vol. 36, pp. 163-170 (2009)      2009年8月   [招待有り]
In ultra dense and hot regions realized in stellar core-collapse, neutrinos take a major role in the energy and momentum transports. We investigate the growth of the magnetorotational instability (MRI) in neutrino viscous media by using linear and...
Masada, Y. & Sano, T.
The Astrophysical Journal   (689) 1234   2008年8月
Axisymmetric magnetorotational instability (MRI) in viscous accretion disks
is investigated by linear analysis and two-dimensional nonlinear simulations.
The linear growth of the viscous MRI is characterized by the Reynolds number
defined as $R_{\...
Youhei Masada, Shigehiro Nagataki, Kazunari Shibata, Toshio Terasawa
Publications of the Astronomical Society of Japan   (62) 1093-1102   2008年3月   [査読有り]
We present a theoretical model describing magnetar giant flares on the basis
of solar flare/coronal mass ejection theory. In our model, a preflare activity
plays a crucial role in driving evaporating flows and supplying baryonic
matters into the m...
Zeeman Spectrum from a Magnetically Triggered Jet
Suzaki, R., Masada, Y. & Kamaya, H.
Publications of the Astronomical Society of Japan   (60) 911   2008年   [査読有り]
Masada, Y., Kawanaka, N., Sano, T., & Shibata, K.
The Astrophysical Journal   (663) 437   2007年   [査読有り]
The central engine of gamma-ray bursts (GRBs) is believed to be a hot and
dense disk with hyperaccretion onto a few solar-mass black hole. We investigate
where the magnetorotational instability (MRI) actively operates in the
hyperaccretion disk, w...
Masada, Y., Sano, T., & Shibata, K.
The Astrophysical Journal   (655) 447   2007年   [査読有り]
Neutrino radiation takes a major role in the momentum, heat, and lepton
transports in proto-neutron stars (PNSs). These diffusive processes affect the
growth of magnetorotational instability (MRI) in PNSs. We perform a local
linear analysis for th...
Masada, Y., Sano, T., & Takabe, H.
The Astrophysical Journal   (641) 447   2006年   [査読有り]
We investigate the stability of differentially rotating proto-neutron stars
(PNSs) with a toroidal magnetic field. Stability criteria for nonaxisymmetric
MHD instabilities are derived using a local linear analysis. PNSs are expected
to have much s...

Misc

 
政田 洋平
プラズマ核融合学会誌2015年10月号      2015年10月   [依頼有り]
政田 洋平
天文月報【2015年10月号 (EUREKA)】      2015年10月   [依頼有り]

書籍等出版物

 
小学校で理科を教えるための理科ミニマム ~小学校教員を目指す学生と理科の苦手な現職教員のために~
政田 洋平 (担当:分担執筆)
2018年4月   

講演・口頭発表等

 
Numerical Modeling of Solar and Stellar Dynamos - Current Status and Future Perspectives - [招待有り]
Youhei MASADA
1st Asia-Pacific Conference on Plasma Physics   2017年9月   
Spontaneous Formation of Surface Magnetic Structure from Dynamo-maintained Magnetic Flux: The Impact of Strong Stratification [招待有り]
Youhei MASADA
COSPAR 2016 (The 41th COSPAR Scientific Assembly: Solar and Stellar Dynamos and Magnetic Flux Emergence   2016年6月   
Organization of Coherent Magnetic Fields in Turbulent Thermal Convection [招待有り]
Youhei MASADA
NASA LWS Workshop on Solar Dynamo Frontiers: Helioseismology, 3D Modeling, and Data Assimilation   2015年6月   

担当経験のある科目

 

競争的資金等の研究課題

 
乱流超新星:自己無撞着な乱流モデルで解き明かす星の終末(研究分担者)
科学研究費補助金: 基盤研究(B)
研究期間: 2018年4月 - 2022年3月    代表者: 横井 喜充
太陽磁場の状態遷移:電磁流体計算で探る太陽活動のグランドミニマムへのトリガー
科学研究費補助金: 基盤研究(C)
研究期間: 2018年4月 - 2021年3月    代表者: 政田 洋平
平均場理論に基づく3次元太陽全球ダイナモモデルの開発
科学研究費補助金: 新学術領域(公募研究)
研究期間: 2018年4月 - 2020年3月    代表者: 政田 洋平
相補的磁気流体モデリングで迫る太陽黒点の起源
科学研究費補助金: 若手研究(B)
研究期間: 2015年4月 - 2018年3月    代表者: 政田 洋平
太陽活動の長期予報の実現へ向けた太陽タコクライン層の基礎研究
科学研究費補助金: 若手研究(B)
研究期間: 2012年4月 - 2015年3月    代表者: 政田 洋平

社会貢献活動

 
望遠鏡でみる活動する太陽
【講師】  愛知県  あいちSTEM能力育成事業「知の探究講座」  2015年8月 - 2018年8月
【講師】  四日市市立博物館  四日市市立博物館宇宙塾  2017年8月
【講師】  フロムページ  夢ナビ TALK/ライブ 2018  (講義No.09087 地球の命運を握る太陽の「磁石」!?)  2018年7月
【講師, 運営参加・支援】  愛知教育大学  愛知教育大学天文台一般公開