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Solar-B Fact Sheet
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What is Solar-B?
Solar-B is an ISAS mission proposed as a follow-on to the highly successful Japan/US/UK Yohkoh (Solar-A) collaboration. The mission consists of a coordinated set of optical, EUV and X-ray instruments that will apply a systems approach to the interaction between the Sun's magnetic field and its high temperature, ionized atmosphere. The result will be an improved understanding of the mechanisms which give rise to solar magnetic variability and how this variability modulates the total solar output and creates the driving force behind space weather. Why Solar-B? Solar-B will, for the first time, provide quantitative measurements of the full vector magnetic field on small enough scales to resolve elemental flux tubes. The field of view and sensitivity allow changes in the magnetic energy to be related to both steady state (coronal heating) and transient changes (flares, coronal mass ejections) in the solar atmosphere. Solar-B is an excellent opportunity for highly leveraged US participation in a major mission that will greatly advance our understanding of the crucial first link in the Sun-Earth connection. The estimated cost to NASA is about $65M, a quarter to a third of the total cost of the mission. Solar-B is planned to start in FY99, launch in FY06, and operate for at least 3 years. Science Objectives: 1. Creation and Destruction of the Sun's Magnetic Field: Magnetic fields permeate all space and play an important role in shaping the universe on all scales. The fields are continuously being generated by dynamos in stellar interiors and swept out into space by stellar winds. The solar dynamo is sufficiently near and operates on a short enough period, 11 years, that it can be studied directly. 2. Modulation of the Sun's Luminosity: During the last decade observations from space have led to the profound discovery that the total output of energy from the Sun is not constant but varies in phase with the magnetic activity cycle. The amplitude of this variation, over the single cycle measured, though small was only a factor of three to five below the level required for a significant climatic response. Solar-B will make the first observations with resolution, wavelength coverage, and time span adequate to determine the mechanism for the magnetic modulation of solar luminosity. 3. Generation of UV and X Radiation: The Sun is a powerful and highly variable source of ultraviolet, X-rays and energetic particles, which are known to have major effects on our environment. This high energy radiation must be due to the annihilation of magnetic energy in the Sun's atmosphere, the chromosphere and corona. Due to its broad complement of instruments with high spatial and spectral resolution, Solar-B will be able to study processes such as magnetic reconnection and wave dissipation that are believed to be responsible for the conversion of magnetic energy into UV and X radiation. 4. Eruption and Expansion of the Sun's Atmosphere The million-degree corona continually expands outward, becoming a supersonic wind that blows past the Earth, buffeting the geomagnetic field and energizing the upper atmosphere. In addition, large parts of the corona are seen to erupt, blasting through the solar wind and causing major magnetic disturbances at Earth. Solar-B will provide accurate measurements of magnetic fields, electric currents, and velocity fields, thus revealing the root causes of the Sun's eruptions. Key Spacecraft Characteristics:
Proposed Solar-B Instrument Complement
Focal Plane Package (FPP) Vector Magnetograph: Focal Plane Package (FPP) Spectrograph: X-Ray Telescope (XRT): EUV Imaging Spectrograph (EIS): Solar-B: An International Collaboration: Solar-B Responsibilities
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Mitzi Adams, mitzi.l.adams@nasa.gov, (256) 961-7626 Mail Code XD12, NASA/Marshall Space Flight Center, Huntsville, AL 35812
Mail Code XD12, NASA/Marshall Space Flight Center, Huntsville, AL 35812
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