[Previous] | [Session 51] | [Next]
H. Zirin (Caltech), R. Cameron (Science University of Tokyo)
We present new observations of weak solar magnetic fields with a technique, which we term the spectro-videomagnetograph (SPVMG) which permits direct measurement of splittings as small as 200 gauss. Using the technique of Stenflo we compared the Stokes V-component for the 5250 and 5247 lines. Contrary to Stenflo’s results, we find no evidence for strong fields with small filling factor; i. e., the field strengths measured as 200 gaussare really 200 gauss and not some stronger field partly filling the sample. For the weakest measured fields this cannot be absolutely established, but the evidence supports the existence of field elements at least as weak as 200 gauss.
Observations of active regions also yield new results. In many cases of fields near inversion lines, we find doubled sets of Zeeman components, as well as “flags,” broad components, usually confined to one side of the line, extending to displacements corresponding to thousands of gauss, with no corresponding component on the opposite side of the line. We show examples of these spectra, along with slit jaw images, but have only a limited understanding of the field structures they represent. We also have examples of the V-splitting increasing as we approach the inversion line. We are struggling to understand these and will at least show them, with or without explanation.
Finally, the regions involving these anomalous Zeeman patterns seem to flare more frequently, although statistics are limited.
This work has been supported by the NSF under ATM-9726147.