Local helioseismology and correlation tracking analysis of surface structures in realistic simulations of solar convection

被引:39
作者
Georgobiani, Dali [1 ]
Zhao, Junwei
Kosovichev, Alexander G.
Benson, David
Stein, Robert F.
Nordlund, Ake
机构
[1] Stanford Univ, Hansen Expt Phys Lab, Stanford, CA 94305 USA
[2] Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA
[3] Univ Copenhagen, Niels Bohr Inst, DK-2100 Copenhagen, Denmark
基金
美国国家科学基金会;
关键词
convection; methods : numerical; Sun : oscillations;
D O I
10.1086/511148
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We apply time-distance helioseismology, local correlation tracking, and Fourier spatial-temporal filtering methods to realistic supergranule scale simulations of solar convection and compare the results with high-resolution observations from the Solar and Heliospheric Observatory (SOHO) Michelson Doppler Imager (MDI). Our objective is to investigate the surface and subsurface convective structures and test helioseismic measurements. The size and grid of the computational domain are sufficient to resolve various convective scales from granulation to supergranulation. The spatial velocity spectrum is approximately a power law for scales larger than granules, with a continuous decrease in velocity amplitude with increasing size. Aside from granulation no special scales exist, although a small enhancement in power at supergranulation scales can be seen. We calculate the time-distance diagram for f- and p-modes and show that it is consistent with the SOHO MDI observations. From the simulation data we calculate travel-time maps for surface gravity waves (f- mode). We also apply correlation tracking to the simulated vertical velocity in the photosphere to calculate the corresponding horizontal flows. We compare both of these to the actual large-scale (filtered) simulation velocities. All three methods reveal similar large-scale convective patterns and provide an initial test of time-distance methods.
引用
收藏
页码:1157 / 1161
页数:5
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