This award supports a three-year collaborative research project between Professor Phillip Scherrer of Stanford University and Professor Hiromoto Shibahashi of the University of Tokyo in Japan. The researchers will undertake a study of local-area helioseismology 118. Local-area helioseismology enables researchers to investigate subsurface flows and small-scale magnetic fields, which have been beyond the reach of 'traditional' helioseismology based on observation of normal modes of solar oscillations. Combined with 'traditional' solar physics and with 'traditional' helioseismology, local-area helioseismology can pave the way to the understanding of the solar activity cycle, and the Sun itself as an astrophysical plasma laboratory. The collaboration aims at advancing local-area helioseismology, with active American solar observation programs (GONG and MDI/SOHO) and the Japanese program (Solar-B). The proposed research is focused on developing new methods of data analyses and theoretical interpretations and inferences. First, they will develop methods of data analysis and interpretation for the local-area helioseismology and analyze the data from the currently running projects, to carry out 3D tomography for flow and sound-speed anomaly due to the magnetic field, and to detect the leakage of wave into the chromosphere. If they can detect waves that travel to the backside of the Sun and them come back, through the central region of the Sun, probing the solar core will be possible too. Second, they will investigate the possibility of local-area helioseismology using very high-resolution velocity field data such as is expected from the Solar Optical Telescope (SOT) on-board Solar-B and other future high-resolution ground-based and space projects.
The project brings together the efforts of two laboratories that have complementary expertise and research capabilities. This research advances international human resources through the participation of graduate students. Through the exchange of ideas and technology, this project will broaden our base of basic knowledge and promote international understanding and cooperation. The researchers plan to publish results of their research in scientific journals and report on the findings at scientific meetings.
