G. Marklund Space & Plasma Physics, School of Electrical Engineering, KTH Stockholm, Cluster multi-probing of the aurora above and within the acceleration region [email protected]www.spp.ee.kth.se C2 C4 C1 C3 eastern bulge middle surge EFW meeting, IRF-U, 24-25 Aug 2011
13
Embed
G. Marklund Space & Plasma Physics, School of Electrical Engineering, KTH Stockholm, Cluster multi-probing of the aurora above and within the acceleration.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
G. Marklund
Space & Plasma Physics, School of Electrical Engineering, KTH
Stockholm,
Cluster multi-probing of the aurora above and within the acceleration region
Göran Marklund S. Sadeghi, J. Cumnock, T. Karlsson, P.-A. Lindqvist, Space & Plasma Physics, KTH, Sweden
H. Nilsson, Swedish Institute of Space Physics, Sweden
J. Pickett, Dept of Physics and Astronomy, U. of Iowa, USA
A. Masson, ESA/ ESTEC, NL
C. Forsyth, A. Fazakerley, MSSL, University College, UK
E. A. Lucek, Imperial College, London, UK.
Y. Zhang, Johns Hopkins University, APL, USA
Cluster AAR study team
EVENT aurora distrib geomagnetic activity Objectives, status
Event 1.29 May 200912:15-12:35 UT
S hemisphere
Mapping of surge and bulge using Cluster data from different MLT crossings meridional & lat current closure
On-going study, Sadeghi et al. 2011
Event 2.31 May 200921:05-21:35 UT
S hemisphere
Electrodynamic coupling of surge head arc and horn arc, origin of deep density cavity in between
On-going study, Marklund et al. 2011
Event 3.5 June 200915:30-16:00 UT
S hemisphere
Electrodynamics of double arc system, interaction between Alfvénic and qs acceleration in PCB and R1 of upward currents
in print JGR, Marklund et al, 2011
Event 4.5 June 200916:50-17:15 UT
N hemisphere Phys. Rev. Lett, Marklund et al 2011
DMSP F16
Cluster
On-going AAR studies and recent publications
F16
First 2-D mappingof AAR of large-scale auroral arc
C2
C4
C1
C3
eastern bulge
middle surge
EVENT I 29 May 200912:15-12:35 UTS hemisphere
Orbit & auroral geometry
Approach 1.
The Bvectors indicate local FAC sheet orientations. which may be related F16 auroral sheet orientations This is one way to infer the bulge motion between the times of the Cluster crossings and the image time
Geomagnetic conditions
Bvectors along Cluster orbits
1 hr MLT
C1 Central Bulge
12:33 UT
12:17 UT
The widths match for a W-ward displace-ment of the C1 trajectory by 1 hr of MLT
The bulge moved 1 hr of MLT in 16 minimplying a W-ward speed of 0.7 km/s
Approach 2To estimate the width of the upward FAC region from Cluster data, scale it to the Ionosphere, and find the location where this width matches that of DMSP aurora
C3 Eastern Bulge
C3
C3 lagged behind C1 by 9 min. The C3 crossing took place 7 min prior to 12:33 UT, implying a W-ward reldisplacement of 0.4 MLT of the C3 trajectory