1. THEMIS/ GBO SciRR splinter 1 UCB/SSL, 06/02/2003 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 THEMIS Program History (or how you go from a Unex to a Midex) Sub-Launch mittedDate QUATRO/UNEX1998mid-2001 QUATRO/SMEX200008/2004 THEMIS/MIDEX200108/2006 GBOs substituted the loss of credible use of IMAGE for auroral onset determination

2. THEMIS/ GBO SciRR splinter 2 UCB/SSL, 06/02/2003 THEMIS primary objectives Aurora Understand substorm onset and evolution (baseline mission, primary objective) As a minimum: Where does substorm eruption start? (ionosphere, CD, Rx ?). MAGNETOSPHERE SOLAR WIND EQUATORIAL PLANE Themis overcomes: Meridional onset confinement (GBOs) Mapping distortions (in situ probes) Global timing (GBOs-probes)

3. THEMIS/ GBO SciRR splinter 3 UCB/SSL, 06/02/2003 Events that comprise the substorm Current Disruption Auroral Eruption Reconnection

4. THEMIS/ GBO SciRR splinter 4 UCB/SSL, 06/02/2003 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

5. THEMIS/ GBO SciRR splinter 5 UCB/SSL, 06/02/2003 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

6. THEMIS/ GBO SciRR splinter 6 UCB/SSL, 06/02/2003 Mission Science Objectives in a Nutshell Design goal; Requirement is less stringent (see next slide) Minimum mission CSR, Table E-1

7. THEMIS/ GBO SciRR splinter 7 UCB/SSL, 06/02/2003 Primary Objective Mission Requirements CSR, Figure E-1 A CSR, Figure E-2 Onset seen from ground: Each line is 0.5 degrees in latitude (56km) and longitude (31km). [Friedrich E. et al. 2001] Maps to 1R E in space Baseline is 10

8. THEMIS/ GBO SciRR splinter 8 UCB/SSL, 06/02/2003 GBO Derived Requirements CSR, Figure F-1/B Same for both minimum and baseline science Comes from (see next slide): (1) Substorm width = 3-4 MLThrs (2) Earth motion w/r/t onset = 3-4 MLT hrs Need 6-8 hrs of MLT station coverage Comes from (see next slide): (3) Earth and P3/4/5 move in same direction: Both cover 4 MLThrs in 12 hrs I gain 4MLT hrs of coverage.

9. THEMIS/ GBO SciRR splinter 9 UCB/SSL, 06/02/2003 Actual conjunction times in 1 st year Points illustrated here: (1) Substorm width = 2-4 MLThrs (2) Earth motion w/r/t onset = 3-4 MLT hrs (3) Earth and P3/4/5 move in same direction: Both cover 4 MLThrs in 12 hrs. (2) (1) (3) A 12 hr alignment (typical) Note: It may be best to ensure P3/4 at apogee in geo-stationary mode over central Canada rather than at fixed (6:30) UT * Favors Western Canada * Helps arrive at dayside with same strategy GBO Conjunctions with THEMIS Probes

10. THEMIS/ GBO SciRR splinter 10 UCB/SSL, 06/02/2003 Ancillary (contributed) GBO Sites Existing THEMIS partnerships (CSR Table E-15) Additional collaborations discussed with: FMI (Scandinavia)

11. THEMIS/ GBO SciRR splinter 11 UCB/SSL, 06/02/2003 GBO-Related L1 Requirements; Rev H 4.1.1.1 [Baseline] Determine substorm onset time and substorm meridian magnetic local time (MLT) using ground ASIs (one per MLT hr) and GMAGs (two per MLT hr) with t_res<30s and dMLT<6 degrees respectively, in an 8hr geographic local time sector including the US. 4.1.1.1 [Minimum] Determine substorm onset time and substorm meridian magnetic local time (MLT) using GMAGs (at least one per MLT hr) with t_res<30s and dMLT<6 degrees respectively, in a 6hr geographic local time sector including the US.

12. THEMIS/ GBO SciRR splinter 12 UCB/SSL, 06/02/2003 EPO GMAGs: inspire students; excite public; provide determination of onset meridian “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 Total eclipse ’98, SF Exploratorium SFUSD Teachers ‘01 RHESSI Solar Camp ‘00 10 mid-latitude states selected (8 Space Grant contacts) Existing design Building starts in October Sites supplement north-south chains in US

13. THEMIS/ GBO SciRR splinter 13 UCB/SSL, 06/02/2003 Site Locations and Roles Summary GBO-GMAGs (CSR Figure F-44) EPO-GMAGs (Site Visit EPO Talk) GBO member roles (CSR Table F-31)