Studies of the Subsurface Structure of Solar Active Regions by Inversion of Phase Shifts and Acoustic Intensity Measured with Taiwan Oscillation Network Data (IV)

The three-dimensional distribution of phase travel time perturbation in an active region below the solar surface can be constructed with the technique of time-distance method and acoustic imaging. We use the regularized least-squares inversion method and obtain preliminary results of three-dimensional distribution of relative sound speed perturbation. The other two inversion methods, optimally localized averages method and truncated singular value decomposition method, gain different results from that of the regularized least-squares method according to previous researches. We will study the two methods in the coming year. The phase velocity perturbation measured using acoustic imaging can be expressed as an integral of the product of the wave-speed perturbation and a kernel. By applying different kernels, we can use our inversion method to invert acoustic intensity and gain the distribution of wave absorption factor. Recently, we use TON (Taiwan Oscillation Network) data together with time-distance method and find some interesting phenomena never been discovered before. But again, the vertical resolution of the results is unclear. We will have to apply the inversion technique to the results in order that we will have enough confident to publish them.

Project ID:PA9308-0422
External Project ID:NSC93-2112-M182-005