Current helicity and magnetic field anisotropy in solar active regionстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 22 февраля 2016 г.
Аннотация:The electric current helicity density χ = ijkbi
∂bk ∂xj
Q4 contains six terms, where bi are components
of the magnetic field. Due to the observational limitations, only four of the above
six terms can be inferred from solar photospheric vector magnetograms. By comparing the
results for simulation we distinguished the statistical difference of above six terms for isotropic
and anisotropic cases. We estimated the relative degree of anisotropy for three typical active
regions and found that it is of order 0.8 which means the assumption of local isotropy for
the observable current helicity density terms is generally not satisfied for solar active regions.
Upon studies of the statistical properties of the anisotropy of magnetic field of solar active
regions with latitudes and with evolution in the solar cycle, we conclude that the consistency
of that assumption of local homogeneity and isotropy requires further analysis in the light of
our findings.