Generation of Artificial Data in Support of SDO-HMI
Nagi N. Mansour, NASA ARC
Alan Wray, NASA ARC
Thomas Hartlep, Stanford CTR
Alexander Kosovichev, Stanford HEPL
Thomas Duvall, NASA GSFC
Mark Miesch, UCAR
Two efforts in progress:
(1) Direct simulation of wave propagation in solar interior
(2) Large-eddy simulation of the near-surface convection zone
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∂t ′ ρ = −Φ
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∂t Φ = −∇2 c 2 ′ ρ ( ) +1
r2∂r (r
2g ′ ρ )
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+ f
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−σ ′ ρ
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−σΦ
Randomforcing
DampingLayer aboveSurface
Wave equation
Equations
Direct Simulation of Wave Propagation in the Solar Interior
• Spherical harmonics, and Basis-Spline in radial direction
• Resolution in all directions adjustable with r• Treatment of coordinate singularity by
enforcing regularity condition at the center
• Non-reflecting boundary by means of a damping layer at the top
• Temporally random forcing of each spherical harmonics mode
NumericalMethod
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′ ρ l,m (r) = r lP(r2)
Example of B-Splines
OscillationPowerSpectraradial-symmetricSound Speed of aStandard Solar Model
with gravity term
without gravity term
StellarBox
• Rectangular geometry
• 50 50 43 Mm
• Compressible, radiation-hydro equations
• LTE radiation, 14 ray angular quadrature
• Non-ideal (tabular) EOS; tabular, binned opacity
• 4th order Padé derivatives
• 3rd (or 4th) order Runge-Kutta in time
• No-penetration, hydrostatic-pressure b.c.’s
• MPI parallelization
StellarBox MPI code
500x500x500
0
2
4
6
8
10
12
0 100 200 300 400 500 600
Number of processors
Mega-updates/sec
Scaling results on Columbia
Current status
• 500500500 on 100 processors (typically)• ~7-8 hour runs• 700-800 steps/run• Also used on brown dwarf stars
Vertical velocity in an x-z plane
QuickTime™ and aBMP decompressor
are needed to see this picture.
Enstrophy ( ||2 ) in an x-z plane
QuickTime™ and aBMP decompressor
are needed to see this picture.
