Kinematical Hydromagnetic Theory and its Application to the Low Solar Photosphere.

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view Abstract Citations (163) References (26) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Kinematical Hydromagnetic Theory and its Application to the Low Solar Photosphere. Parker, E. N. Abstract The magnetic field B is computed from the hydromagnetic equations for a variety of given velocity fields';. The velocity fields are classified as turbulent if their time correlation extends no more than their scale a divided by their characteristic velocity v. The velocity fields are classified as persistent if their time correlation extends beyond a/v but is short compared with the magnetic diffusion time a2/X (X = c2/4ir , and as stationary if their time correlation extends beyond a2/X. It is shown that turbulent fluid motions in the solar photosphere generate r.m.s. fields which are a few times the large-scale field strength B0 in the photosphere. Where B0> 20 gauss, this leads to equipartition of energy between the turbulent magnetic and velocity fields. It is & njectured that, since plages occupy the areas on the solar surface where B0> 20 gauss, there may be some connection between equipartition and plage formation. It is shown that motions tend to draw the field into concentrated sheets and filaments. The observed supergranulation in the solar atmosphere tends to concentrate vertical magnetic fields around the edges of the cells, where the field density may become 102 times larger than in the interior of the cell. It is shown that stationary motions tend to exclude the magnetic field from the region of fluid motion. A number of examples are given to show the distortion of the field by the forces exerted by the fluid diffusing through it. It is to be hoped that observations will yield simultaneous velocity and magnetic-field maps so that quantitative comparison can be made with the expected theoretical results. Publication: The Astrophysical Journal Pub Date: August 1963 DOI: 10.1086/147663 Bibcode: 1963ApJ...138..552P full text sources ADS |