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

Dali Georgobiani, Junwei Zhao, Alexander G. Kosovichev, David Benson, Robert F. Stein, Åke Nordlund

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

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 traveltime 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.

Original languageEnglish (US)
Pages (from-to)1157-1161
Number of pages5
JournalAstrophysical Journal
Volume657
Issue number2 I
DOIs
StatePublished - Mar 10 2007
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Convection
  • Methods: numerical
  • Sun: oscillations

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