Location of the High-Latitude
Reconnection Site on 14 February 2003
S. Eriksson1, M. M. Kuznetsova2,
M. W. Dunlop3, and H. Reme4
1LASP,
University of Colorado, Boulder, CO, USA
2NASA/GSFC, Greenbelt, MD, USA
3Rutherford Appleton Laboratory, Chilton, UK
4Centre d’Etude Spatiale des Rayonnements, Toulouse, France
Contact: eriksson@lasp.colorado.edu
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
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 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 15-20o. 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).
Lobe Reconnection Schematic
Dungey [1963]
(courtesy of J. C. Dorelli, UNH)
Cluster orbits 1800-2010 UT
Side view
19
View from above
20 UT
18
Solar Direction
Cluster C1
Cluster C2
Cluster C3
Cluster C4
Solar Direction
Solar Direction
Ni [cm-3]
T [K]
Vx [km/s]
Vy [km/s]
Vz [km/s]
Bx [nT]
By [nT]
Bz [nT]
Northward IMF
18:30
19:00
19:30
20:00
20:30 UT
Solar Wind
Input
to
BATSRUS MHD
Simulation
at the CCMC
Cluster C1
Cluster C3
Ni
MHD @ C1
MHD @ C3
Bx
By
Bz
Vx
Vy
Vz
18:00
19:00
20:00
18:00
19:00
20:00
Cusp Schematic - Cluster FGM
Lobe field
Cluster C1
Cluster C3
Dayside closed field
z
x
Direction of magnetic field
Vx
Vy
Vz
Bx
By
Bz
18:40
19:40
20:40
18:40
19:40
20:40
Walen Test: Quantitative agreement with
high-latitude magnetic reconnection:
Northward IMF
Vx
Vy
Vz


v  B / 0
x-comp
y-comp
z-comp
Bx
By
Bz
Same Cluster C1 & C3 data 1840-2040 UT: Ni & V merged


v  B / 0

 
Rx   v v
How well do these -dV directions
compare with MHD simulation
results of Vx and B?
MHD Simulation
Northward IMF
YZ GSM Plane
1900 UT
B
Vx
J||
Vy
Cluster C1 position
~1800-1900 UT
Northward IMF MHD Simulation
XZ GSM Plane at 1900 UT
Vx
Vy
B
P
Northward IMF: Vx
-dV for northward IMF
-dV for southward IMF
Northward IMF: B
-dV for northward IMF
-dV for southward IMF
Northward IMF MHD Simulation
XZ GSM Plane at 1900 UT
Vx
jxB vectors shown on top Vx and Vy
Vy
Northward IMF MHD Simulation
XZ GSM Plane at 1900 UT
Vx
jxB vectors shown on top Vx and Vy
….field lines shown as well
Vy
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 15-20o. 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).
Walen Test: Quantitative agreement with
high-latitude magnetic reconnection
magnetosheath
Bn
magnetotail lobe
z
x