1. THEMIS/Science Briefing 1 NASA/HQ, 03/12/2003 T IME H ISTORY OF E VENTS AND M ACROSCALE I NTERACTIONS DURING S UBSTORMS (THEMIS) RESOLVING THE PHYSICS OF ONSET AND EVOLUTION OF SUBSTORMS Science Team Principal Investigator Vassilis Angelopoulos, UCB EPO Lead Nahide Craig, UCB Program Manager Peter Harvey, UCB Industrial Partner SWALES Aerospace

2. THEMIS/Science Briefing 2 NASA/HQ, 03/12/2003 Auroral eruptions and substorms Auroral eruptions… Aurora …are a manifestation of magnetospheric substorms MAGNETOSPHERE SOLAR WIND EQUATORIAL PLANE

3. THEMIS/Science Briefing 3 NASA/HQ, 03/12/2003 Most compelling science driver The onset and evolution of magnetospheric substorms SEC Objective #1: “Understand the changing flow of energy and matter through … planetary magnetospheres” National Academy of Sciences: “A strategic question in space physics” SEC Objective#2: Explore fundamental physical processes of plasma systems SEC Objective #3: “Define origins and societal impacts of variability in SEC” Substorms are fundamental… …and important to the US space program …for understanding magnetospheric transport … for basic physics … for space weather and society

4. THEMIS/Science Briefing 4 NASA/HQ, 03/12/2003 Events occuring during a substorm Current Disruption Auroral Eruption Reconnection

5. THEMIS/Science Briefing 5 NASA/HQ, 03/12/2003 Flows Primary Objectives, Goals and Means Onset and evolution of substorms Time History of Events (Onset)… –Delineate cause and effect Measure When  Where … and Macroscale Interactions during Substorms (Evolution) –Coupling in the magnetosphere Measure plasma flows and waves –Coupling to the ionosphere Measure currents and structures Distinguishes among competing models: impartially answers a well-posed question… Current Disruption Model timeEvent 0 secCurrent Disruption 30 secAuroral Eruption 60 secReconnection Reconnection Model timeEvent 0 secReconnection 90 secCurrent Disruption 120 secAuroral Eruption ? ? Rarefaction wave ? P1 P2 P3 P4 P5 GBO …as implied by Themis, goddess of impartial justice

6. THEMIS/Science Briefing 6 NASA/HQ, 03/12/2003 Mission elements Probe conjunctions along Sun-Earth line recur once per 4 days over North America. Ground based observatories completely cover North American sector; determine auroral breakup within 1-3s … … while THEMIS’s space-based probes determine onset of Current Disruption and Reconnection each within <10s. : Ground Based Observatory

7. THEMIS/Science Briefing 7 NASA/HQ, 03/12/2003 Mission overview: Fault-tolerant design has constellation and instrument redundancy D2925-10 @ CCAS Instrument I&T UCB Mission I&T Swales Encapsulation & launch BGS Operations UCB Probe instruments: ESA: Thermal plasma SST: Super-thermal plasma FGM: Low frequency magnetic field SCM: High frequency magnetic field EFI: Electric field Ground SST ESA EFIa EFIs FGM SCM T spin =3s

8. THEMIS/Science Briefing 8 NASA/HQ, 03/12/2003 Mission provides definitive answer to the substorm question. P1 P2 P3 P4 P5 Simultaneous observations in the key regions Ideal geometries for tens of substorms Data rates / time resolution exceed requirements Analysis tools available from Cluster, ISTP, FAST Experienced co-Is are leaders on both sides of substorm controversy Custom event simulations aid analysis; demonstrate closure in realistic plasma flow fields.

9. THEMIS/Science Briefing 9 NASA/HQ, 03/12/2003 Most important science result and its science impact Answers how substorms operate – Explains how magnetospheres process solar wind energy –Explains how auroras erupt –Explains how a fundamental space weather process operates MERCURY: 10 min EARTH: 3.75 hrs JUPITER: days ASTROSPHERE GALACTIC CONFINEMENT SUBSTORM RECURRENCE:

10. THEMIS/Science Briefing 10 NASA/HQ, 03/12/2003 First bonus: What produces storm-time “killer” MeV electrons? Affect satellites and humans in space Source: – Radially inward diffusion? – Wave acceleration at radiation belt? THEMIS: –Tracks radial motion of electrons Measures source and diffusion Frequent crossings –Measures E, B waves locally ANIK telecommunication satellites lost for days to weeks during space storm

11. THEMIS/Science Briefing 11 NASA/HQ, 03/12/2003 Second bonus: What controls efficiency of solar wind – magnetosphere coupling? Important for solar wind energy transfer in Geospace Need to determine how: – Localized pristine solar wind features… – …interact with magnetosphere THEMIS: – Alignments track evolution of solar wind – Inner probes determine entry type/size

12. THEMIS/Science Briefing 12 NASA/HQ, 03/12/2003 Progress for space science Answers: “How do substorms operate?” – One of the oldest and most important questions in Geophysics – A turning point in our understanding of the dynamic magnetosphere “What accelerates storm-time ‘killer’ electrons?” – A significant contribution to space weather science “What controls efficiency of solar wind – magnetosphere coupling?” – Provides global context of Solar Wind – Magnetosphere interaction

13. THEMIS/Science Briefing 13 NASA/HQ, 03/12/2003 Aligned with all primary SEC objectives –Answers question deemed “strategic” by NAS –Pre-requisite to space weather prediction Fits NASA SEC vision for: –Studying dynamic Geospace interactions –Increased spatial resolution and coverage –Low cost, highly integrated probes –Science and technology SEC pathfinder Complementary with LWS, MMS, Cluster –THEMIS studies global interactions, others study local effects –Extended THEMIS mission provides global context for MMS Benefits to US space science program and timeliness

14. THEMIS/Science Briefing 14 NASA/HQ, 03/12/2003 Most important aspect for public Fundamental mechanism in Sun-Earth interaction resolved –Auroral eruption trigger identified in space –Substorms, key to predicting space weather –Mystery of how Earth’s environment processes energy blowing from Sun resolved

15. THEMIS/Science Briefing 15 NASA/HQ, 03/12/2003 Experienced EPO team: inspires young minds and excites public “Student-operated NASA instruments detect space storms affecting satellites and humans in space” –EPO ground magnetometers at K-12 schools: Promote inquiry-based and theme-based instruction Allow hands-on student participation Targets under-served communities: –Magnetically clean rural institutions: Tribal and Hispanic-serving Expands on existing partnerships and resources: –FAST and RHESSI practices –Space Grant Consortium –Science museums Total eclipse ’98, SF Exploratorium SFUSD Teachers ‘01 RHESSI Solar Camp ‘00

16. THEMIS/Science Briefing 16 NASA/HQ, 03/12/2003 Uniqueness Solves major long-standing question in magnetospheric physics –Self-sufficient, ideally complements current SEC line Provides unique view of the dynamic magnetosphere –Unprecedented probe and probe/ground alignments study space-time evolution Inspires K-12 students about space and Sun-Earth connections –Hands-on involvement of student magnetometer curators First University-led multi-satellite project –Expands NASA partnership with Academia –Trains scientific and technological workforce of the future

17. THEMIS/Science Briefing 17 NASA/HQ, 03/12/2003 Summary  Fully answers a compelling science question  Ushers a new era in magnetospheric physics  Benefits US space science program  Unique  Engages public  Inspires students  Timely: Science and technology pathfinder