[IGPP Everyone] TODAY: Space Physics Seminar, Friday Jan. 9th: Removing the Veil of Field-Aligned Currents (M. Connors, Athabasca)

[Emmanuel V. Masongsong]

SPACE PHYSICS SEMINAR 

DEPARTMENT OF EARTH, PLANETARY, AND SPACE SCIENCES 

DEPARTMENT OF ATMOSPHERIC AND OCEANIC SCIENCES 

UNIVERSITY OF CALIFORNIA, LOS ANGELES 

(EPSS M288A, AOS M275A ) 







Martin Connors 


Athabasca University 





Removing the Veil of Field-Aligned Current Ambiguity 








Abstract: 


Field-aligned electric current flow is an essential characteristic of near-Earth space. It forms important parts of the Iijima-Potemra global current systems and the Substorm Current Wedge, associated respectively with steady state and impulsive events in the magnetosphere. Ground magnetometers can be considered as the largest “geosynchronous” constellation, returning magnetic data from many points and with high time resolution. However, the fact that they integrate over large volumes of space is a mixed blessing, giving rise to ambiguity in interpretation. Fukushima’s Theorem about the ambiguity of ground-based data inversion arose in an important historical context as spacecraft measurements started to be made, but now appears to be misunderstood. Thus it deserves examination. Similarly, the Iijima-Potemra system could be discovered only by averaging satellite data, with weak ground perturbations due to its solenoidal nature. The recently upgraded AMPERE satellite project, using the commercial Iridium satellites to give a global view of radial (essentially field-aligned) currents, allows removal of much ambiguity, and promises to allow optimal use of ground magnetic data. 




Friday, January 9th, 2015 

Room 6704 Geology 

3:30 - 5:00 PM 



Refreshments served after the seminar in Room 6850. 



In-Charge 
V. Angelopoulos 


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.igpp.ucla.edu/pipermail/everyone/attachments/20150109/737d0b1a/attachment-0001.html>