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Session 16 - Magnetic Fields I.
Oral session, Tuesday, July 01
Ballroom A, Chair: Edward DeLuca

[16.05] On The Detection of Currents and Parker's Objection

A. Skumanich (HAO/NCAR), M. Semel (DASOP, Obs Paris-Meudon)

We propose a way to derive a radial electric current density (hereafter current) from vector magnetograms that is free of any particular choice of the two possible azimuths for the plane of the sky (POS) field. The method is applied to active region data obtained with the Advanced Stokes Polarimeter. A comparison of this current density with that derived for two particular sets of possible azimuth assignments allows one to evaluate the appropriateness of each set and to detect the occurrence of current sheets, i.e. field discontinuities. A minimum current constructed from ambiguity-free POS and line-of-sight currents allows one to verify the detection of currents in general. Parker's scenario leads to a current distribution that is statistically distributed about zero, looks like noise and is also discontinuous. We observe such noise as well as continuous and significant currents. We conclude that the unresolved magnetic field is not necessarily always in the form of individual flux tubes.

Program listing for Tuesday