Takashi Sekii （ NAOJ ） Local helioseismology at small scales

HMI/AIA Science Team Meeting 2006, Monterey 2 I am talking about…  How SDO and Solar-B can work together for high-resolution local helioseismology, for subphotospheric dynamics  What kind of challenges are ahead

HMI/AIA Science Team Meeting 2006, Monterey 3 Solar-B  A J/US/UK/European collaboration  To be launched in September 2006

HMI/AIA Science Team Meeting 2006, Monterey 4 Solar Optical Telescope  50-cm Solar Optical Telescope (SOT) produces high-resolution Dopplergrams that can be used for local helioseismology FOV narrow but high spatial resolution  Not suited for probing deep layers  （ Horizontally) high-resolution view of the solar interior For more details, ask Katsukawa-san

HMI/AIA Science Team Meeting 2006, Monterey 5 HMI and SOT  Spatial resolution and FOV HMI/SDO: 1 arcsec, the entire disc SOT/Solar-B: 0.2 arcsec, 328”x164”(*)  size of individual flux tubes: ~ km (0.2 arcsec=150km)  HMI/SOT Simultaneous observation will be very useful as it combines broader coverage (HMI) and higher resolution (SOT)

HMI/AIA Science Team Meeting 2006, Monterey 6 High-resolution local helioseismology (1/4)  Is it worth doing? Is there any wavefield power at such a small scale?

HMI/AIA Science Team Meeting 2006, Monterey 7 High-resolution local helioseismology (2/4)  MDI high-resolution power spectrum No resonant p modes above ℓ≈2000 The f-mode frequency ∝ sqrt(ℓ)

HMI/AIA Science Team Meeting 2006, Monterey 8 High-resolution local helioseismology (3/4)  Sekii et al 2001: MDI[I](left) versus La Palma SVST G-band (right, Berger et al 1998)

HMI/AIA Science Team Meeting 2006, Monterey 9 High-resolution local helioseismology (4/4)  La Palma result shows improvement in (mainly p-mode) time-distance S/N in <10,000 km range, down to <1,000km  Local helioseismology with high- degree f modes is an obvious thing to do, but p-mode seismology will also benefits from higher-resolution

HMI/AIA Science Team Meeting 2006, Monterey 10 Challenges (1/2)  Propagation of waves in magnetized fluid when wavelength is similar to the size of individual flux tubes And use them for diagnostic purpose Can we ‘observe’ kernels? (Duvall, Gizon & Birch)

HMI/AIA Science Team Meeting 2006, Monterey 11 Challenges (2/2)  What is the smartest way to merge f- mode data and p-mode data (or do we just merge them)  Similarly, how do we merge HMI data and SOT data?  T-d analysis in magnetic regions Comparing magnetic-line data (HMI & SOT) and non-magnetic-line data (SOT) should be useful (not just for HR stuff!)