The nonlinear development of the kink instability of a magnetic flux tube initially lying in mechanical equilibrium in the deep convection zone is presented. The unstable evolution is started by a small-amplitude sinusoidal perturbation of the shape of the flux tube in a vertical plane. As a result of the development of the instability, the lower

IAUC 4489 available at Central Bureau for Astronomical Telegrams. IAUC 4489 available at Central Bureau for Astronomical Telegrams.

Not Available

Not Available

The Cometary Knots in the Helix Nebula have shown themselves to be formed of a head which is a photoionized surface, optically thick to Lyman continuum radiation, on the central star facing sides of neutral clumps and a cometary tails photionized by the diffuse radiation field. In this study we will present the results of a photoionization model of

We present results of numerical 3D simulation of propagation of MHD waves in sunspots. We used two self consistent magnetohydrostatic background models of sunspots. There are two main differences between these models: (i) the topology of the magnetic field and (ii) dependence of the horizontal profile of the sound speed on depth. The model with