Saku Tsuneta to Give talk at Peyton Hall
Tuesday November 3, 2009 - Peyton Hall Auditorium
4:30pm - 5:30pm, A reception will follow at Grand Central.
"HINODE - A New Solar Observatory in Space"
It is a fascinating fact that a solitary star like the Sun emits intense
X-rays from its outer atmosphere. Observations with the Japan-US Yohkoh
satellite showed that all the sporadic heating from X-class flares to
ubiquitous tiny bursts in the solar corona is due to magnetic reconnection,
which generates jets, heats and non-thermal particles. Magnetic fields do
dissipate in the solar corona with a time scale 1012 faster than that of the
classical Ohmic dissipation. Though this leads to an attractive conjecture
that the solar corona is heated by nano-bursts as initially proposed by
Parker, the precise mechanism for the heating the solar corona and for the
solar wind acceleration mechanism is not known.
These activities on the surface of the star are driven by magnetic fields
created by dynamo mechanism. The magnetic field strength on the surface of
the Sun exceeds 1kG, while that at the bottom of the convection zone may
exceed 100kG. They are too strong, far stronger than the equi-partition
magnetic field strength. We have not yet known dynamo mechanism that can
amplify field strength upto the equi-partition field strength, and mechanism
to produce field strength beyond that threshold.
The concept of Hinode is that two X-ray and EUV telescopes observe the
dissipation part of the magnetic life-cycle, while the visible light
telescope simultaneously observes the generation and transport of magnetic
field. Discoveries with Hinode include MHD waves in spicules, prominences
and on the photosphere, ubiquitous jets in chromospheres, ubiquitous
transient horizontal magnetic fields on the photosphere suggesting local
dynamo process, supersonic down-flow and convective collapse resulting in
super equi-partition magnetic field strength, emergence of large-scale flux
rope from below the photosphere, kG-magnetic patches in the polar regions,
identification of the origin of slow solar wind, and enigmatic fine-scale
flows in the prominence. This talk summarizes how the new results from
Hinode are addressing these critical questions as well as probing
fundamental physical processes that will have applications in many other
scenarios across the universe.