MHD tomography using interplanetary scintillation measurement

Abstract

The MHD tomography analysis, an advanced version of the computer-assisted tomography (CAT) analysis for interplanetary scintillation (IPS) observational data, is presented. When combined with a MHD simulation, the CAT analysis can reconstruct the MHD-based three-dimensional solar wind structure within 1 AU from the IPS line-of-sight integrated velocity data. At the same time, the MHD code can simulate the actual conditions in the heliosphere beyond 1 AU by utilizing the results of the MHD tomography analysis and extrapolate to r ≥ 1 AU. The present MHD tomography aims to reconstruct the global structure of corotating solar wind, under the assumption that the global solar wind does not vary significantly in time during one Carrington rotation. The reconstructed three-dimensional solar wind variables including interplanetary magnetic field (IMF) are compared with the in situ measurement data made at the Ulysses spacecraft and nearby Earth, and good correlations are obtained. We anticipate that the combination of MHD simulation and the IPS tomography will enhance solar wind research and space weather prediction algorithms.