On the magnetic fields confinement in the flux tubes of variable diameter

The problem of the static confinement is considered for the magnetic field concentrated in a thin axisymmetric flux tube. For the magnetic structures observed on the Sun's surface, the radial component of the field Hsub(r) is shown to make an appreciable contribution to the pressure balance (the ''funnel'' effect). The model calculations have been made for the magnetic flux tube with the field distribution satisfying the similarity assumption. The magnetic field on the axis declines with the height z exponentially, approximately esup(-z/lambda), where lambda is the magnetic scale-height. For the flux tubes with the cross-section radius a > or approximately 4.0 lambda, the confinement has been found possible even under positive pressure difference between the tube and the surrounding photosphere. The temperature and pressure profiles are derived under the different assmuptions about the geometrical parameters of the system