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Session 11 - Sun-Earth Connections Roadmap.
Oral session, Saturday, June 28
Ballroom A, Chair: Loren Acton
Solar-B is the ISAS mission follow-on to the highly successful Japan/US/UK Yohkoh (Solar-A) collaboration. The overall science goal of Solar-B is to determine the magnetic origins of the solar variability that Yohkoh and SOHO have been observing, and that drive the Sun-Earth connection. The mission complement consists of an optical vector magnetograph and spectrograph, an X-ray telescope, and an XUV spectroheliograph. This coordinated instrument package will answer many of the outstanding questions in solar physics. We know that processes hidden deep within the Sun generate surface activity in an 11-year cycle. Emerging magnetic field topology can reveal the workings of this dynamo process. Solar-B will observe the emerging magnetic field and, for the first time, its twist in detail over large regions of the Sun. Measurement of the solar``constant" shows the Sun to be less luminous at sunspot cycle minima. Extremely small scale features in the solar photosphere cause the solar cycle changes in the luminosity. Solar-B will make the first observations with spatial resolution, wavelength coverage, and sampling adequate to determine the role of these features in the long-term solar luminosity changes. The solar UV and X-radiation originates in the chromosphere and corona, where temperatures rise to over one million degrees and where the plasma is highly dynamic, often erupting into the heliosphere. Solar-B will open a new window on the underlying causes of coronal heating and eruptions by providing the first accurate measurements of the Sun's magnetic field and electric currents, simultaneous with detailed observations of the coronal dynamics.
Programmatically, Solar-B represents a unique opportunity for NASA to participate with a highly reliable partner in a frontier-probe class mission at the cost of a MIDEX. Solar-B also represents an ideal opportunity for continuing the Solar-Terrestrial Probe Line of the Sun-Earth Connections Theme.
Program listing for Saturday