ИСТИНА

We select the results of experimental observations on AMPTE/CCE demonstrating the formation of local minima of the magnetic field inside the magnetosphere. Such minima can appear due to diamagnetic effect of increased plasma pressure. We developed a nonlinear model of the distortion of the dipole magnetic field by fixed distribution of plasma pressure suggesting the validity of the condition of the magnetostatic equilibrium and plasma pressure isotropy. Cases with finite plasma parameter (the relation of plasma pressure to the magnetic pressure) are analyzed. We obtain the distributions of Bz component of the magnetic field and the volumes of the magnetic flux tube at the equatorial plane. We show that local not surrounding the Earth contours Bmin=const (where Bmin is the minimal value of the magnetic field on the magnetic field line) are formed in the case of finite value of plasma pressure. The relevance of the obtained rezults of modeling for the explanation of the appearance of observed magnetic field minima are discussed.