In situ observations of plasma and magnetic fields in vicinity of comets have shown existence of diamagnetic disturbances of the plasma of high amplitudes. The physical nature of such disturbances is not well understood by now. In this paper we note that the same to observed features have some kinds of nonlinear solitary vortex type disturbances. These type of motion is supported by plasma density, magnetic field or pressure gradients, which provides effective gravity in system.To analyze this possibility the early developed two-dimensional kinetic description of the magnetized plasma flow with mass loading is used. The solutions of the solitary vortex type superimposed on the regular plasma flow are considered both analytically and numerically. Numerical results are used to derive the relations between solitary vortex and averaged plasma flow parameters. This results are discussed in connection with the experimental observations of the solar wind plasma flow interaction with comet.