Solar-B Mission

S. Tsuneta (National Astronomical Observatory of Japan)

SOLAR-B to be launched in the summer of 2006 will carry optical, EUV and
X-ray telescopes. The prime purpose is to track the sub-surface  generation
and transport of magnetic fields and its eventual dissipation in the corona.
The Solar Optical Telescope (SOT) has unprecedented 0.2 arcsec resolution,
and polarimetric and helioseismic approaches with SOT allow us to
simultaneously observe the magnetic fields on and below the photosphere.
Configuration of sub-surface and emergent magnetic flux tubes, emergence,
submergence, and reconnection of magnetic fields, disintegration and
transport of sunspot fields, direct detection of various MHD waves, role of
magnetic helicity and surface flows, nature of elemental flux tubes are
among the massive topics to be pursued with SOT. SOT also brings fusion of
observations and numerical MHD simulation. Time-dependent boundary-data of
magnetic and velocity fields may be directly fed to the MHD system in the
computer to predict its evolution. Its coronal consequence is observed with
the two X/EUV telescopes. The EUV imaging spectrometer brings 1-arcsec
velocity maps of coronal plasma 10 times as sensitive as SOHO. An immediate
topic is the detection of flows associated with magnetic reconnection.   The
X-ray telescope (1 arcsec resolution) sensitive to 1MK to 30 MK
simultaneously provides Yohkoh-like and TRACE-like images. Multiplicity of
temperature in spatial and time domain is the key to understand the heating
of the corona.