Physics
Scientific paper
Nov 1996
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996r%26qe...39..930a&link_type=abstract
Radiophysics and Quantum Electronics, Volume 39, Issue 11-12, pp. 930-934
Physics
Scientific paper
The problem of accumulation of magnetic field energy in an active region (AR) as the energy of electric currents in the AR atmosphere is not yet completely clear. Along with the commonly accepted concept of generation of electric current systems in an AR due to large- scale shearing motions at the photospheric level [1,2], another possibility of magnetic field energy accumulation has recently been proposed theoretically [3]. Assuming that the AR magnetic field evolves via a sequence of force- free configurations, Seehafer shows that the energy of small- scale field and velocity fluctuations can be transformed into that of large-scale current systems of an AR (alpha-effect). The necessary condition for the alpha-effect to exist is the presence of the sign- dominant current helicity H c = B · (∇×B) in the volume is considered. The purpose of this paper is to clarify the fulfillment of this condition in various ARs. Based on the measurements of magnetic field vector in 40 active regions of the maximum of the 22nd cycle we calculated the current helicity of the field Bz · (∇×B) z in the photosphere and obtained the following results. In 36 ARs we found a significant imbalance of the current helicity of the field (5 to 75%) such that in 33 ARs the excess of the current helicity was positive in the southern hemisphere and negative in the northern hemisphere. Therefore, in ARs the necessary condition for transfer of the energy of small-scale fluctuations of the field and velocity into the energy of large- scale electric currents in ARs is fulfilled rather frequently.
Abramenko Valentina I.
Wang Tie-Jun
Yurchishin V. B.
No associations
LandOfFree
Accumulation of magnetic field energy in an active region due to the alpha-effect does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Accumulation of magnetic field energy in an active region due to the alpha-effect, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Accumulation of magnetic field energy in an active region due to the alpha-effect will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1750952