Giant Convective Cell 観観観観観 観観観観観(2005.3.6) 観観
Feb 02, 2016
Giant Convective Cell 観測と理論
太陽雑誌会(2005.3.6)北井
概要• はじめに• 理論の紹介
GLOBAL-SCALE TURBULENT CONVECTION AND MAGNETIC DYNAMO ACTION IN THE SOLAR ENVELOPE
A. S. Brun, M. S. Miesch, J. Toomre (Ap J, 614:1073–1098, 2004)
• 観測の紹介 PHOTOMETRIC SEARCH FOR SOLAR GIANT CONVECTION CELLS W.-H. Chiang, L.D. Petro, P.V. Foukal (Solar Phy. 110, p129,1987)
THE DETECTION OF GIANT VELOCITY CELLS ON THE SUN J.G. Beck, T.L. Duvall, Jr, P.H.Sherrer, and J.H. Hoeksema( Soho6/GONG98 Workshop, 199
8) 62-DAYS AROUND THE SUN: A SEARCH FOR SUPERGRANULAR EVOLUTION AND GIAN
T CELLS L.H. Strous and G.W. Simon ( ASP conf. series 140, 161, 1988)
• SMART データによる観測計画案
Giant Convetive Cell
GLOBAL-SCALE TURBULENT CONVECTIONBrun’s Numerical Simulation
• 3D spherical shell• Anelastic MHD Equation Neglection of Sound speed :infinite
• Thermodynamic Quantities
Sherical symmetiric component
+fluctuation • D : Viscous tensor
t
GLOBAL-SCALE TURBULENT CONVECTIONBrun’s Numerical Simulation
• Boundary condition
• Shell 0.72-0.98 Solar Radius
GLOBAL-SCALE TURBULENT CONVECTIONBrun’s Numerical Simulation
GLOBAL-SCALE TURBULENT CONVECTIONBrun’s Numerical Simulation
GLOBAL-SCALE TURBULENT CONVECTIONBrun’s Numerical Simulation
観測(1) Chiang et al
• Kitt Peak
• Search for large-scale temperature fluctuation
• Photometry atλ525.6nm by 512-diode Reticon through spectrometer
• Spatial scan perpendicular to the solar rotation axis
• 15days, 4 N-zone + 4 S-zone scan
観測(1) Chiang et al
観測(1) Chiang et al
• Temperature Fluctuation
RMS = 0.33K ( 0.023%)
Spatial scale 80-240Mm
⇒ Detection of Giant Cell ?
( Simulation predicts ΔT≒1K)
観測 (2) Beck et al
• SOHO/MDI Doppler data
Daily averaged frame / 1440 frames taken in 1-min cadence
• Low resolution data (12deg square)
May 1996-Sep 1997 : 505days time series
• Medium resolution data ( 32min square )
May 1996-Nov 1997 : 576days time series
観測 (2) Beck et al (Low Resolution)
27-days long-lived feature
Lifetime : 4months
V(horizontal) : 3.6m/s
L(horizontal) : 44deg
観測 (2) Beck et al (Medium Resolution)
Velocity amplitude : 3.2m/s
Cell : Horizontally elongated
( 56 deg x 7 deg )
⇒ Detection of Giant Cells
観測(3) Strous & Simon • 62-day time-series of full-dis
k SOHO/MDI Dopplergrams obtained at a one-minute cadence
• Subtraction of background Doppler signal (5-degree polynomial fitting)
• Spatial smoothing ( 85” and 171” )
• Movie Watch ⇒ No giant cells detect
ed
観測(3) Strous & Simon
• Feature Tracking ( SG cells as tracers )
観測(3) Strous & Simon
Result
Unexplained horizontal velocity field of 30m/sec
⇒ Detection of Giant cell inconclusive
Hida-FMT での解析
Hida-FMT での解析
Hida-FMT での解析
Hida-FMT での解析
SMARTでの解析• Full-disk Hα wing image
• LCTM ( Even-Odd test, Reverse test )
• Tracer : Supergranulation
• Spatial resolution : 0.5” ( FMT 4”)
Merit : Tracers all over the disk
Deficit : Interrupttion by nights
END