1. Location of the High-Latitude Reconnection Site on 14 February 2003 S. Eriksson 1, M. M. Kuznetsova 2, M. W. Dunlop 3, and H. Reme 4 1 LASP, University of Colorado, Boulder, CO, USA 2 NASA/GSFC, Greenbelt, MD, USA 3 Rutherford Appleton Laboratory, Chilton, UK 4 Centre d’Etude Spatiale des Rayonnements, Toulouse, France Contact: eriksson@lasp.colorado.edueriksson@lasp.colorado.edu

2. Outline Northward IMF Remote Cluster lobe reconnection observations 14 February 2003 1840-1955 UT (C1 and C3) BATSRUS MHD simulation comparison http://ccmc.gsfc.nasa.gov [c.f. “Stefan_Eriksson_060905_1”] Summary

3. The relative location of the magnetopause reconnection site as predicted by MHD simulations is in good agreement with the remote observations by the Cluster s/c. This will be shown for northward IMF conditions during the 14 February 2003 event. Initial estimates suggest that the angle between Rx and Rs=[Rm-Rc] is 15-20 o. Here, Rx= - dV / |dV|, Rm is the location of the MHD reconnection site and Rc is the Cluster location at the time of the observed jet (dV). The actual magnitude of the enhanced plasma velocity due to the jxB force is off by an order of magnitude (~40 km/s versus ~400 km/s).

4. Lobe Reconnection Schematic Dungey [1963] (courtesy of J. C. Dorelli, UNH)

5. Cluster C1 Cluster C2 Cluster C3 Cluster C4 Solar Direction View from aboveSide view 18 19 20 UT Cluster orbits 1800-2010 UT

6. Solar Wind Input to BATSRUS MHD Simulation at the CCMC Ni [cm-3] T [K] Vx [km/s] Vy [km/s] Vz [km/s] Bx [nT] By [nT] Bz [nT] Northward IMF 19:0019:3020:0020:30 UT18:30

7. Vx Vy Vz Bz By Bx Ni MHD @ C1 Cluster C1Cluster C3 MHD @ C3 18:0020:0019:0018:0020:0019:00

8. Cusp Schematic - Cluster FGM Cluster C3 Cluster C1 Direction of magnetic field Lobe field Dayside closed field x z

9. Bx By Bz Vx Vy Vz 18:4019:4020:4018:4019:4020:40

10. Bx By Bz Vx Vy Vz x-comp y-comp z-comp Walen Test: Quantitative agreement with high-latitude magnetic reconnection : Northward IMF Same Cluster C1 & C3 data 1840-2040 UT: Ni & V merged

12. How well do these -dV directions compare with MHD simulation results of Vx and B?

13. Cluster C1 position ~1800-1900 UT BVx VyJ || MHD Simulation Northward IMF YZ GSM Plane 1900 UT

14. Vy Vx B Northward IMF MHD Simulation XZ GSM Plane at 1900 UT P

15. Northward IMF: Vx -dV for southward IMF -dV for northward IMF

16. Northward IMF: B -dV for southward IMF -dV for northward IMF

17. Vx Vy Northward IMF MHD Simulation XZ GSM Plane at 1900 UT jxB vectors shown on top Vx and Vy

18. Northward IMF MHD Simulation XZ GSM Plane at 1900 UT Vx Vy jxB vectors shown on top Vx and Vy ….field lines shown as well

19. Summary The relative location of the magnetopause reconnection site as predicted by MHD simulations is in good agreement with the remote observations by the Cluster s/c. This was shown for northward IMF conditions during the 14 February 2003 event. Initial estimates suggest that the angle between Rx and Rs=[Rm-Rc] is 15-20 o. Here, Rx= - dV / |dV|, Rm is the location of the MHD reconnection site and Rc is the Cluster location at the time of the observed jet (dV). The actual magnitude of the enhanced plasma velocity due to the jxB force is off by an order of magnitude (~40 km/s versus ~400 km/s).

20. Walen Test: Quantitative agreement with high-latitude magnetic reconnection Bn z x magnetotail lobe magnetosheath