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    National Tsing Hua University Institutional Repository > 理學院 > 物理系 > 會議論文  >  Acoustic imaging and subsurface structure of solar active regions


    Please use this identifier to cite or link to this item: http://nthur.lib.nthu.edu.tw/dspace/handle/987654321/56198


    Title: Acoustic imaging and subsurface structure of solar active regions
    Authors: Chang Hsiangkuang;Chou Deanyi
    教師: 張祥光
    Date: 1999
    Publisher: American Society of Primatologists
    Relation: Third Advances in Solar Physics Euroconference: Magnetic Fields and Oscillations, ASP Conference Series, 1999, Pages 171-175
    Keywords: acoustic imaging
    astronomical techniques
    solar magnetism
    solar pulsations
    sunspots
    Abstract: Using high spatial resolution helioseismic data taken with the TON (Taiwan Oscillation Network) instruments, we have developed a method, called “acoustic imaging”, to probe the structure and properties of solar active regions. The method of acoustic imaging, based on a time-distance relationship, coherently collects observed acoustic signals at the surface to reconstruct acoustic signals in the solar interior. We have successfully obtained acoustic images of several sunspot groups for various depths below the surface. Signatures of magnetic regions are clearly revealed, both in the sense of acoustic absorption and phase shift. At the surface, correspondence of these features between K-line images and reconstructed acoustic images is obvious. They extend down to about 30-40 Mm below the surface. However, a firm conclusion cannot be drawn until the issue of depth resolution of this method is better understood. Acoustic absorption images constructed with p-mode signals in different frequency ranges are presented. It is found that acoustic absorption in magnetic regions is stronger for 3- and 4-mHz than for 5- and 6-mHz. The dependence on the spherical harmonic degree l is very weak
    URI: http://adsabs.harvard.edu/full/1999ASPC..184..171C
    http://www.asp.org/
    http://nthur.lib.nthu.edu.tw/dspace/handle/987654321/56198
    Appears in Collections:[物理系] 會議論文

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