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Space Weather

Space Weather. Diamond. O. C. St Cyr and Joseph M Davila NASA-Goddard Space Flight Center. Space Weather Experts Meeting, Vienna, February 2014. Motivation. Solar wind observations from L1 provide 30-60 min warning for energetic particle events

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Space Weather

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  1. Space Weather Diamond O. C. St Cyr and Joseph M Davila NASA-Goddard Space Flight Center Space Weather Experts Meeting, Vienna, February 2014

  2. Motivation • Solar wind observations from L1 provide 30-60 min warning for energetic particle events • Sunjammer (a NASA technology demonstration) will be stationed at ~0.02 AU, about 2x the L1 distance • A solar wind monitor located as far as 0.3 AU upstream of Earth would provide a reliable predictive capability (Lindsay et al. 1999) Sunjammer uses a solar sail to counteract a portion of the Sun’s gravitational attraction to allow station keeping inside of the classical L1. Compared to the DSCOVR and Sunjammer concepts, Space Weather Diamond offers 10X the L-1 warning of solar wind disturbances

  3. Predicting Terrestrial Weather • Weather in the mid-west today is Washington’s weather tomorrow. • Midrange forecasts are based on upstream observations Derecho Hourly Time Lapse June 29, 2012

  4. Predicting Space Weather • Like terrestrial weather, space weather that originates at the Sun today arrives at Earth 1-3 days later • Midrange forecasts based on observations at the Sun provide long-term forecasting CME observed by STEREO February 15, 2008 Earth Sun Similar story for solar wind variations and high speed streams

  5. Mission Description Four spin-stabilized spacecraft in eccentric heliocentric orbits, phased so that they appear to surround Earth Monitor spacecraft nearest Sun continuously for space weather prediction; the remaining three spacecraft operate autonomously and record data for periodic playback Measurement Strategy Solar wind plasma, interplanetary magnetic field, radio burst detector, and energetic particle sensors on all spacecraft One spacecraft also carries a white-light heliospheric mapper Technology Requirements Heritage designs available today Minimal risk for significant return Space Weather Diamond • St. Cyr et al., Journal of Atmospheric and Solar-Terrestrial Physics, 62, 1,251-1,255, 2000.

  6. Solar-Rotating Frame: looking down on Ecliptic Plane Mission Orbit L1 Earth To Sun Heliocentric Frame: looking down on Ecliptic Plane Mission Orbit InsertionManeuver Venus TransferOrbit Mercury  Mars Earth Distant Retrograde Orbit (DRO) Motion • A DRO is a heliocentric orbit which remains in the vicinity of the Earth • In the simulation shown here, the ‘semi-minor axis’ (i.e. the distance closest to the Sun) is 10 x the L-1 distance while the maximum range from Earth is 0.2 AU

  7. DRO Range from Earth DRO Insertion Maneuver

  8. Space Weather Diamond • A four spacecraft constellation provides mapping of the interplanetary medium along the perimeter of an elliptical figure 0.4 AU x 0.2 AU • Seen from the Sun, the constellation subtends an angle +11° centered on Earth

  9. Space Weather Diamond SW Diamond Sunjammer 0.1 AU ACE

  10. Science Questions • Propagation and evolution of Interplanetary Coronal Mass Ejections (ICMEs) • How does the ICME interact with the ambient interplanetary medium? • Tomography of active regions • 3D Magnetic field mapping of active regions and other coronal features

  11. Summary • Forecasts with several days lead time must be based on observations prior to the Earth arrival of CME or solar wind feature • Imaging provides one such opportunity but has line of sight ambiguity • L1 observations provide upstream observation of the solar wind but with only 30-60 min warning • A space weather diamond mission could extend the warning time by a factor of 10

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