Speaker
Mei Zhang
(National Astronomical Observatory of China)
Description
We present our observations on current and kinetic
helicities that provide constrains on solar dynamo models.
We find that: (1) Current helicity in active regions present
a clear hemispheric helicity sign rule but this rule also
shows a solar-cycle variation. (2) Strong and weak magnetic
fields show opposite helicity signs in active regions and
this property may also has a solar-cycle variation. (3) The
hemispheric helicity sign rule is also evident in global
magnetic field outside the active regions and it is
preserved for the whole solar cycle. (4) No solar-cycle
variation on subsurface kinetic helicity presents in local
helioseismology observation, which poses a question on how
could a solar-cycle-independent kinetic helicity produce a
solar-cycle-dependent current helicity. Finally, we will
also present some preliminary results on using above
observational constrains to check two dynamo simulation
models, namely, in Miesch & Brown (2012) and in Fan & Fang
(2014).
Primary author
Mei Zhang
(National Astronomical Observatory of China)
