A method applying the theoretical solution of the radiative transfer problem with the magnetic field to the observed Zeeman line profile is developed. The assumptions of a pure-absorption atmosphere and of no magneto-optical effect allow a model-free determination of the magnetic field averaged along the optical depth. Depth variation of line-profile parameters, such as the Doppler shift, Doppler width, damping constant, magnetic field strength, and tilt of the magnetic line of force, is obtained.The present method of analysis is applied to a penumbral spectrum observed on May 10, 1971 and has shown an inward magnetic field, whose strength is 1500 G, making an angle of 34° against the solar surface, and an outward Evershed flow of 5.6 km s-1, parallel to the magnetic line of force.
Publications of the Astronomical Society of Japan
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