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SDO/HMI Science Team Meeting September 8-11, 2009, Stanford

SDO/HMI Science Team Meeting September 8-11, 2009, Stanford. Sensitivity kernels, artificial data and testing. Konstantin Parchevsky Alexander Kosovichev. Ray kernels. 3D high resolution averaged sound speed ray kernels. Plane parallel vs. spherical kernels. Born kernel.

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SDO/HMI Science Team Meeting September 8-11, 2009, Stanford

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  1. SDO/HMI Science Team Meeting September 8-11, 2009, Stanford Sensitivity kernels, artificial data and testing Konstantin Parchevsky Alexander Kosovichev

  2. Ray kernels

  3. 3D high resolution averagedsound speed ray kernels

  4. Plane parallel vs.spherical kernels

  5. Born kernel

  6. 3D averaged sound speedBorn kernels

  7. Ray and Born Kernels

  8. Artificial data • We developed 3D code for numerical simulation of wave propagation inside the Sun (pure acoustics, MHD, and MHD+background velocities). • Non-uniform background model (both horizontally and vertically) with non-uniform magnetic field (for the magnetic instance of the code). User can specify a profile of the sound speed perturbation. • Localized single and multiple random sources. User can specify the depth, size, frequency range, type (force or pressure). • Additional damping (friction type term) can be specified.

  9. Characteristic featuresof the code • We put great efforts to make results of simulations as close to the real Sun as possible for the linear code. • Dispersion-relation-preserving spatial scheme ( • Realistic top boundary condition (waves with frequency higher than acoustic cut-off frequency leave the domain). • Modification of the background state to remove the convective instability.

  10. k- diagram Verifies almost the entire code: dispersion relation, numerical dispersion, numerical damping, boundary conditions, background model, source spectrum. position of the ridges, relative ridge ampl., overall power distr., cut-off frequency.

  11. Effect of non-uniform distribution of sources Model I, wave field is masked Model II, sources are masked Model III, both wave field and sources are masked Ann. radii = 6.2-11.2, 8.7-14.5, 14.5-19.4 Mm

  12. Conclusion • Ray path and Born high-res. sensitivity kernels are computed. • Linear 3D MHD code was developed and extensively tested. • Artificial data (both pure acoustic & magnetic) for testing and calibration of helioseismic techniques are ready for blind tests.

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