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Magnetic Field Spectroheliograms from the San Fernando Observatory

Published online by Cambridge University Press:  14 August 2015

Dale Vrabec
Dale Vrabec*
Affiliation:
San Fernando Observatory, The Aerospace Corporation, El Segundo, Calif., U.S.A.

Abstract

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Zeeman spectroheliograms of photospheric magnetic fields (longitudinal component) in the CaI 6102.7 Å 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 spectroheliograms, 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, including 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 Hα 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.

Type
Part III: Observations of Sunspot and Active Region Magnetic Fields
Information
Symposium - International Astronomical Union , Volume 43: Solar Magnetic Fields , 1971 , pp. 329 - 339
Copyright
Copyright © Reidel 1971 

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