Magnetic Field Spectroheliograms from the San Fernando Observatory

Abstract

Abstract. Zeeman spectroheliograms of photospheric magnetic fields (longitudinal component) in the Cai 6102.7 A line are being obtained with the new 61-cm vacuum solar telescope and spectroheliograph, using the Leighton technique. The structure of the magnetic field network appears identical to the bright photospheric network visible in the cores of many Fraunhofer lines and in CN spectro heliograms, with the exception that polarities are distinguished. This supports the evolving concept that solar magnetic fields outside of sunspots exist in small concentrations of essentially vertically oriented field, roughly clumped to form a network imbedded in the otherwise field-free photosphere. A timelapse spectroheliogram movie sequence spanning 6 hr revealed changes in the magnetic fields, in cluding a systematic outward streaming of small magnetic knots of both polarities within annular areas surrounding several sunspots. The photospheric magnetic fields and a series of filtergrams taken at various wavelengths in the Ha profile starting in the far wing are intercompared in an effort to demonstrate that the dark strands of arch filament systems (AFS) and fibrils map magnetic field lines in the chromosphere. An example of an active region in which the magnetic fields assume a distinct spiral structure is presented.

Magnetoconvection on the Solar Surface

“…This to 15 min, measurements must be made in a time is the well known moat flow in which magnetic short compared to this lifetime. In addition, features flow radially out from the sunspot because the 5-sin oscillation is also present in (Sheeley, 1969(Sheeley, , 1971; Sheeley and Bhatnagar, the movies (Title et al, 1986(Title et al, ), measurements 1971Vrabec, 1971). We also observe that the must be separated by considerably less than 2.5 pore region acts as a large sink, especially for sin.…”

“…Several observers (Simon, 1967;Muiler and Mena, 1987;Title et al, 1987) have attempted to *Operated by the Association of Universities for relate the motions of granules to magnetic strucResearch in Astronomy, Inc., under contract with tures, and many others (Vrabec, 1971;Smithson, the National Science Foundation. Partial support 1973;Schroter and Wohl, 1975;Masher, 1977; is provided by the USAF under a Memorandum of Martin, 1988;Title et al, 1987) of the sunspot penumbra into the surrounding…”