The eruption of the filament with the kink fashion is often regarded as a signature of the kink instability. However, the kink instability threshold for the filament magnetic structure has been not widely understood. Using the Hα observation from the New Vacuum Solar Telescope (NVST), we present a partial eruptive filament. In the eruption, a filament thread appeared to split from the middle portion of the filament and to break out in a kinklike fashion. During this period, the left filament material remained below, which erupted without the kinking motion later on. The coronal magnetic field lines associated with the filament are obtained from the nonlinear force-free field (NLFFF) extrapolations using the 12 minutes cadence vector magnetograms of the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory (SDO). We studied the extrapolated field lines passing through the magnetic dips that are in good agreement with the observed filament. The field lines are non-uniformly twisted and appear to be made up by two twisted flux ropes winding about each other. One of them has higher twist than the other, and the highly twisted one has its dips aligned with the kinking eruptive thread at the beginning of its eruption. Before the eruption, moreover, the highly twisted flux rope was found to expand with the approximately constant field twist. In addition, the helicity flux maps deduced from the HMI magnetograms show that some helicity is injected into the overlying magnetic arcade, but no significant helicity is injected into the flux ropes. Accordingly, we suggest that the highly twisted flux rope became kink unstable when the instability threshold declined with the expansion of the flux rope.

-Magnetic field structures on the solar atmosphere are not symmetric distribution in the northern and southern hemispheres, which is an important aspect of quasi-cyclical evolution of magnetic activity indicators that are related to solar dynamo theories. Three standard analysis techniques are applied to analyze the hemispheric coupling (north-south asymmetry and phase asynchrony) of monthly averaged values of solar Ha flare activity over the past 49 years (from 1966 January to 2014 December). The prominent results are as follows: (1) from a global point of view, solar Ha flare activity on both hemispheres are strongly correlated with each other, but the northern hemisphere precedes the southern one with a phase shift of 7 months; (2) the long-range persistence indeed exists in solar Ha flare activity, but the dynamical complexities in the two hemispheres are not identical; (3) the prominent periodicities of Ha flare activity are 17 years full-disk activity cycle and 11 years Schwabe solar cycle, but the short-and mid-term periodicities cannot determined by monthly time series; (4) by comparing the non-parametric rescaling behavior on a point-by-point basis, the hemispheric asynchrony of solar Ha flare activity are estimated to be ranging from several months to tens of months with an average value of 8.7 months. The analysis results could promote our knowledge on the long-range persistence, the quasi-periodic variation, and the hemispheric asynchrony of solar Ha flare activity on both hemispheres, and possibly provide valuable information for the hemispheric interrelation of solar magnetic activity.