Comparison of photospheric current helicity and subsurface kinetic helicity
نویسندگان
چکیده
منابع مشابه
Helicity at Photospheric and Chromospheric Heights
In the solar atmosphere the twist parameter α has the same sign as magnetic helicity. It has been observed using photospheric vector magnetograms that negative/positive helicity is dominant in the northern/southern hemisphere of the Sun. Chromospheric features show dextral/sinistral dominance in the northern/southern hemisphere and sigmoids observed in X-rays also have a dominant sense of rever...
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1 NORDITA, AlbaNova University Center, Roslagstullsbacken 23, SE-10691 Stockholm, Sweden 2 Department of Astronomy, AlbaNova University Center, Stockholm University, SE 10691 Stockholm, Sweden 3 Space Research Institute of the Russian Academy of Sciences Profsoyuznaya 84/32, Moscow 117997, Russia 4 Moscow Institute of Physics and Technology, State University, Institutsky lane 9, Dolgoprudny 141...
متن کامل-effect dynamos with zero kinetic helicity
A simple explicit example of a Roberts-type dynamo is given in which the effect of mean-field electrodynamics exists in spite of pointwise vanishing kinetic helicity of the fluid flow. In this way, it is shown that -effect dynamos do not necessarily require nonzero kinetic helicity. A mean-field theory of Roberts-type dynamos is established within the framework of the second-order correlation a...
متن کاملAlpha-effect dynamos with zero kinetic helicity.
A simple explicit example of a Roberts-type dynamo is given in which the alpha effect of mean-field electrodynamics exists in spite of pointwise vanishing kinetic helicity of the fluid flow. In this way, it is shown that alpha-effect dynamos do not necessarily require nonzero kinetic helicity. A mean-field theory of Roberts-type dynamos is established within the framework of the second-order co...
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Current helicity quantifies the location of twisted and sheared non-potential structures in a magnetic field. We simulate the evolution of magnetic fields in the solar atmosphere in response to flux emergence and shearing by photospheric motions. In our global-scale simulation over many solar rotations the latitudinal distribution of current helicity develops a clear statistical pattern, matchi...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society: Letters
سال: 2009
ISSN: 1745-3925,1745-3933
DOI: 10.1111/j.1745-3933.2008.00615.x