  We analyse the spatial distribution of current helicity in solar active
regions. A comparison of current helicity maps derived from three different
instruments (Helioseismic and Magnetc Imager on board the Solar Dynamics
Observatory, SDO/HMI, Spectro-Polarimeter on board the Hinode, and Solar
Magnetic Field Telescope at the Huairou Solar Observing Station, China,
HSOS/SMFT) is carried out. The comparison showed an excellent correlation
between the maps derived from the spaceborne instruments and moderate
correlation between the maps derived from SDO/HMI and HSOS/SMFT vector
magnetograms. The results suggest that the obtained maps characterize real
spatial distribution of current helicity over an active region. To analyse
intermittency of current helicity, we traditionally use the high-order
structure functions and flatness function approach. The slope of a flatness
function within some range of scales - the flatness exponent - is a measure of
the degree of intermittency. SDO/HMI vector magnetograms for 3 ARs (NOAA 11158,
12494, and 12673) were used to calculate the flatness exponent time variations.
All three ARs exhibited emergence of a new magnetic flux during the
observational interval. The flatness exponent indicated the increase of
intermittency 12-20 hours before the emergence of a new flux. We suppose that
this behaviour can indicate subphotospheric fragmentation or distortion of the
pre-existed electric current system by emerging magnetic flux.
