Quantitative Explanation of Stokes V Asymmetry in Solar Magnetic Flux Tubes

  1. C. T. Russell,
  2. E. R. Priest and
  3. L. C. Lee
  1. S. K. Solanki

Published Online: 21 MAR 2013

DOI: 10.1029/GM058p0185

Physics of Magnetic Flux Ropes

Physics of Magnetic Flux Ropes

How to Cite

Solanki, S. K. (2013) Quantitative Explanation of Stokes V Asymmetry in Solar Magnetic Flux Tubes, in Physics of Magnetic Flux Ropes (eds C. T. Russell, E. R. Priest and L. C. Lee), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM058p0185

Author Information

  1. Department of Mathematical Sciences, University of St. Andrews, St. Andrews, KY16 9SS, Scotland

Publication History

  1. Published Online: 21 MAR 2013
  2. Published Print: 1 JAN 1990

ISBN Information

Print ISBN: 9780875900261

Online ISBN: 9781118663868

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Keywords:

  • Solar photosphere;
  • Magnetic flux;
  • Astrophysics

Summary

Stokes profiles of four spectral lines with very different properties are calculated in a two dimensional flux tube model of a solar magnetic element. The model has empirically derived temperature and magnetic field strength values within the magnetic element and satisfies pressure balance. The considered model can reproduce the asymmetry between the blue and red Stokes V wings, as well as other line parameters observed near disk centre in solar active region plages and the network if it incorporates the following three features: 1) A downflow of 0.5–1.5 km s−1 in the immediate surroundings of the flux tube (but not inside it). 2) A 250–350 K lower temperature in the downflowing non-magnetic atmosphere than in the average quiet sun. 3) A longitudinal wave-like or oscillatory motion with an amplitude of between 1 and 3 km s−1 within the magnetic element. The Stokes V asymmetry is thus seen to be a natural outcome of the current picture of magnetic elements embedded in cool downflowing intergranular lanes and of the presence of relatively large amplitude non-stationary mass motions within magnetic elements. The observations also suggest that the upflowing and the downflowing phases of the waves differ in some important respects.