Hinode "A New Solar Observatory in Space" Hinode "A New Solar Observatory in Space"

It is a remarkable and fascinating fact that a solitary star like the Sun emits intense X-rays from its outer atmosphere. Obser-vations with Japan-US Yohkoh satellite [1] show that all the sporadic heating from major flares to ubiquitous tiny bursts in the solar corona is due to magnetic recon-nection; a process to efficiently annihilate magnetic fields with opposite direction into heat, jets and non-thermal accelera-tion. Magnetic field does dissipate in the corona with time scale 1012 faster than that of the classical Ohmic dissipation. Though this leads to an attractive conjecture that the solar corona in general is heated by ensemble of tiny bursts ([2, 3] and refer-ences therein), precise mechanism for the heating of solar corona and acceleration mechanism of solar wind is, however, unknown. These activities on the surface of the star are driven by magnetic field created by interaction of flow and fields below the photosphere (dynamo mechanism). The magnetic field strength on the surface of the sun exceeds 1 kG, while that at the bot-tom of the convection zone may reach 100 kG. They are too strong, far stronger than the equi-partition magnetic field strength, whose energy is the same as that of the lo-cal convection motion. Though a dynamo mechanism can amplify field strength upto the equi-partition field strength, it is perceived not possible to have field strength beyond the threshold. Such too-strong magnetic field can be found elsewhere in the universe, namely puls-ers (1012G), magneters (1015G), galaxies and clusters of galaxies (a few micro G), which is again too strong in terms of that in early universe (10-17G, [4]). Dynamo mechanism for the sun and these objects is poorly understood