Distribution characteristics of coronal
electric current density as an indicator
for the occurrence of a solar flare
In this paper we investigate the distribution characteristics of the coronal electric current
density in a flare-producing active region (AR12158; SOL2014-09-10) by reconstructing
nonlinear force-free (NLFF) fields from photospheric magnetic field data. A time series
of NLFF fields shows the spatial distribution and its temporal development of coronal
current density in this active region. A fractal dimensional analysis shows that a concentrated
coronal current forms a structure of fractal spatiality. Furthermore, the distribution
function of coronal current density is featured with a double power-law profile, and the
value of electric current density at the breaking point of a double power-law fitting function
shows a noticeable time variation toward the onset of an X-class flare. We discuss
that this quantity will be a useful indicator for the occurrence of a flare.
Reference
Kang, J. H., Magara, T., Inoue, S., Kubo, Y., & Nishizuka, N.
Publication of Astronomical Society of Japan, 68, 101
