ESL MRS. NABULSI. COORDINATING CONJUNCTIONS CORRELATIVE CONJUNCTIONS SUBORDINATE CONJUNCTIONS.
8th Cluster Workshop, Sept 30, 2004 Cluster/DMSP Conjunctions in the Cusp Wayne Keith NASA Goddard...
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Transcript of 8th Cluster Workshop, Sept 30, 2004 Cluster/DMSP Conjunctions in the Cusp Wayne Keith NASA Goddard...
8th Cluster Workshop, Sept 30, 2004
Cluster/DMSP Conjunctions in the Cusp
Wayne KeithNASA Goddard Space Flight Center
With grateful acknowledgements to M. Goldstein, T. Stubbs, D. Winningham, A. Fazakerley, and H. Rème
8th Cluster Workshop, Sept 30, 2004
To what degree are cusp structures comparable from mid to low altitudes?
8th Cluster Workshop, Sept 30, 2004
Finding Magnetic Conjunctions
• Appropriate common (mapped) coordinates• Identify cusp crossings for Cluster• Search Cluster crossings for DMSP
satellites within 5° (~550 km) of Cluster footprint
• Rank quality of DMSP data• Compare relative timing of particle
signatures
8th Cluster Workshop, Sept 30, 2004
Automated Search Procedure• Mapped Cluster center-of-mass coordinates
calculated via T01 and ingested into system• Conjunction software run for all Cluster cusp
crossing times• For times when a DMSP satellite is within a “cusp
box”, check their proximity using:
• If < 5°, write start/stop times to a file• Automatically generate DMSP plot for closest
approach ±2 min€
=cos−1( ˆ R C • ˆ R D )
8th Cluster Workshop, Sept 30, 2004
The score so far:
• January through August 2001 searched• 73 Cluster cusp crossings• 172 DMSP magnetic close-approaches• 53 of which contained “good” particle signatures• 35 Cluster passes contained at least one good DMSP
crossing• 14 good coincidence between closest approach and cusp
signature• 2 conjunctions under study (one in each major Cluster
“cusp season”)
8th Cluster Workshop, Sept 30, 2004
Conclusions
• Cluster/DMSP conjunctions identified using combination of automated and manual search techniques
• Mapped Cluster cusp location usually poleward of DMSP cusp location
• Cusp appears narrow in Invariant Latitude and extended in Magnetic Local time
• Cusp structures appear similar in general, but Cluster data requires more study