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THEMIS: Understanding Substorms & Space Weather

Discover the first results from THEMIS mission and its impact on understanding substorms and space weather. Engage students and the public in space science. Explore future activities and simulations.

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THEMIS: Understanding Substorms & Space Weather

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  1. THEMIS First Results and near future • Introduction, THEMIS overview • First THEMIS results from the tail • First THEMIS results in the dayside • First THEMIS results in the radiation belts • Engaging students and the public • Future activities

  2. Maximizing Substorm Science on THEMIS:Probe Alignments and Ground Conjunctions Simulation: J. Raeder, UNH Visualization: Tom Bridgman,GSFC/SVS Vassilis Angelopoulos, UCLA ESS April 13, 2006

  3. TIME HISTORY OF EVENTS AND MACROSCALE INTERACTIONS DURING SUBSTORMS (THEMIS) • SCIENCE GOALS: • Primary: • “How do substorms operate?” • One of the oldest and most important questions in Geophysics • A turning point in our understanding of the dynamic magnetosphere • First bonus science: • “What accelerates storm-time ‘killer’ electrons?” • A significant contribution to space weather science • Second bonus science: • “What controls efficiency of solar wind – magnetosphere coupling?” • Provides global context of Solar Wind – Magnetosphere interaction RESOLVING THE PHYSICS OF ONSET AND EVOLUTION OF SUBSTORMS Principal Investigator Vassilis Angelopoulos, UCLA EPO Lead Laura Peticolas, UCB Mission Operations Manager Manfred Bester, UCB Industrial Partner ATK Space (SWALES Aerospace Inc.)

  4. THEMIS’s science and impact • THEMIS will answer how substorms operate • Explains how magnetospheres process solar wind energy • Explains how auroras erupt ASTROSPHERE GALACTIC CONFINEMENT SUBSTORM RECURRENCE: MERCURY: 10 min EARTH: 3.75 hrs JUPITER: days

  5. Auroral eruptions and substorms …are a manifestation ofmagnetospheric substorms Auroral eruptions… SOLARWIND Aurora MAGNETOSPHERE EQUATORIAL PLANE

  6. : Ground Based Observatory THEMIS Mission elements Probe conjunctions along Sun-Earth line recur once per 4 days over North America. … while THEMIS’s space-based probes determine onset of Current Disruption and Reconnection each within <10s. Ground based observatories completely cover North American sector; determine auroral breakup within 1-3s …

  7. Substorms in THEMIS GBOs Mende et al, GRL 2007

  8. Discovery of the first indicator of onset on the ground: Pulsations “irregular” of type 1, Burst Ground magnetograms …High-pass filtered … … Downward Current Upward Current 12-48s 48-192s Milling et al., GRL, 2008

  9. EFIs EFIa SCM ESA BGS SST Operations UCB FGM Tspin=3s Instrument I&T UCB Ground Mission overview Release D2925-10 @ CCAS Probe instruments: ESA: ElectroStatic Analyzer(coIs: Carlson and McFadden)SST: Solid State Telescopes (coI: Larson)FGM: FluxGate Magnetometer(coIs: Glassmeier, Auster & Baumjohann)SCM: SearchCoil Magnetometer (coI: Roux) EFI: Electric Field Instrument (coI: Bonnell) Encapsulation & launch Mission I&T UCB

  10. P1 P2 P3 P4 P5 TH-B TH-C TH-D TH-E TH-A 2007-03-23 2007-06-03 Launch=2007-02-17 YGSE 2007-07-15 XGSE 2007-08-30 2007-12-04 First 10 months Angelopoulos, 2008 Space Sci. Rev. Submitted

  11. TH-B TH-C TH-D TH-E TH-A P1 P2 P3 P4 P5 First year baseline orbit YGSE Dayside 12008-08-08 XGSE Tail 12008-02-02 Angelopoulos, 2008 Space Sci. Rev. Submitted

  12. First light: Nature’s welcome. Substorm captured on March 23, 2007 V ~ 350km/s Angelopoulos et al.,First Results from THEMIS, Space Sci. Reviews, 2008 Speed: 1MLT/min

  13. THEMISDetail For ULF waves also see: Keiling et al., GRL, 2008

  14. Z D Y B A V ~ 70km/s 1000 km Remote sensing establishes motion

  15. Z Y X Reconstruction of Field Aligned Currents B FAC By sc B Assuming an outward plasma sheet expansion (evidenced by the |Bx| reduction - interpreted as a diamagnetic effect) the FAC is a pair of oppositely directed current sheets, embeded in an overall outward currentsheet. This is consistent with THEMIS being at the westward edge of the WTS.

  16. Strangeway et al. GRL, 2008observe same signatures on FAST

  17. Timing For further details on timing see: Wenlon Liu et al., GRL, 2008 For event simulation see:Raeder et al., SSR, 2008

  18. Conclusions on March 23 event • Westward expansion speed on the ground ~ 1 MLT hrs/minMaps to 10RE as 200-300km/s westward • Westward observed speed in space (D - E) is ~250km/sConsistent with mapping the speed from the ground up • Hot boundary motion near onset location is an outward expansionObtained using remote sensing and finite gyroradius techniques • Summary: First Observations of Westward Traveling Surge in Space • Similar papers establish the nature of substorm expansion in space: • Zhang, H. et al., GRL, 2008 [February 28, 2007 substorm; FGM only] • Donovan, H., et al., GRL, 2008 [March 13, 2007 substorm; TH-A ESA]

  19. THEMIS at the dayside: First everdetection of a detached flux rope Sphere Dusk MP -,+ Sheath Details, see: Sibeck et al., GRL, 2008

  20. B L N M THEMIS at the dayside: Discovery of remote signatures of flux ropes BN TH-B, C, D, E, A PT TH-B, C, D, E, A TH-B VL,M,N TH-C VL,M,N TH-D VL,M,N TH-E See Liu J., GRL, 2008 Remote signatures of flux ropes: Field compression; velocity inside opposes sheath flow!Trains of flux ropes suggest high reconnection rate. VL,M,N TH-A VL,M,N

  21. THEMIS at the dayside: Significance ofthe apparent preponderance of flux ropes If dissipated in high latitude cusp they add to wave accelerated electrons, and ion outflows at the cusp. If dissipated at the low latitudeboundary, they add to wave acceleration of electrons and ion outflows on field linesalong the auroral oval. Courtesy: X.J. Jia, UCLA Courtesy: N. Omidi, Solana Scientific

  22. THEMIS first direct observation of the birth of the storm-time ring current Ions Electrons Dst storm index TH-B TH-B TH-D TH-D TH-B TH-B See Wang C. P., et al, GRL, 2008Ions penetrate deep into the inner magnetosphere, and remain after storm. Electrons also come close to Earth, but decay fast after storm recovery.

  23. THEMIS tracks, for the first time, a SolarWind shock, and the substorm it triggered. Keika, K. GRL, 2008. THEMIS data quality andavailability is revitalizing coordination amongst allavailable space assets in the panoply of Heliophysics.

  24. THEMIS observations: GRL, JGRand media presentations • 40 Fall AGU presentations • Numerous topical conferences • Media coverage

  25. Inspiring Yound Minds Reaching out to K-12 classes in rural America The Jim Lehrer show: http://www.pbs.org/newshour/bb/science/jan-june07/themis_05-16.html

  26. Data availability, community participation. Maximize discourse and discovery.

  27. Summary • Discoveries to date • In Tail/Substorms • First signature of substorm onset on the ground: Pi1B waves • First measurements of the Westward Traveling Surge in space • First observations of shock propagation through magnetosphere, triggered substorm • In Dayside • First observations of detached flux ropes • Discovery of remote signatures of magnetic reconnection • First in-situ observations of the onset of hot flow anomalies • First direct observations of microphysics of asymmetric reconnection • In Inner Magnetosphere • First observations of the birth of the ring current • Outlook • Constellation in excellent state • Tail conjunctions have started, quality optimal in late February, early March, 2008 • Repeat again from different perspective in 2009 • Long Term • Preparing Senior Review proposal (FY09-12) • Will build on successes of prime mission • The fun has only just started!

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