Driven acoustic oscillations within a vertical magnetic fieldThe effects of a vertical magnetic field on p-mode frequencies, line widths, and eigenfunctions, are examined. A solar model, consisting of a neutrally stable polytropic interior matched to an isothermal chromosphere, is applied. The p-modes are produced by a spatially distributed driver. The atmosphere is threaded by a constant vertical magnetic field. The frequency shifts due to the vertical magnetic field are found to be much smaller than the shifts caused by horizontal fields of similar strength. A large vertical field of 2000 G produces shifts of several nHz. It is found that the frequency shifts decrease with increasing frequency and increase with field strength. The coupling of the acoustic fast mode to the escaping slow modes is inefficient. Constant vertical magnetic field models are therefore incapable of explaining the high level of absorption observed in sunspots and plage.
Document ID
19960014129
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Hindman, Bradley W. (Joint Inst. for Lab. Astrophysics Boulder, CO, United States)
Zweibel, Ellen G. (Joint Inst. for Lab. Astrophysics Boulder, CO, United States)
Cally, P. S. (Monash Univ. Clayton, Australia)
Date Acquired
August 17, 2013
Publication Date
June 1, 1995
Publication Information
Publication: ESA, Proceedings of 4th SOHO on Helioseismology. Volume 2: Posters