[en] Data obtained for dynamics of a plasma stream generated by a coaxial plasma accelerator (PA) are presented. The rates of the front and back portions of the stream moving along the plasma guide are determined by microwave cutoffs. The lifetime of 1,6x10¹³ cm^-3 plasma is found as a function of the external magnetic field and electrode voltage in the PA. Time variation of the electron density is measured by interferometers at wavelengths lambda = 337 and lambda = 10,6μm. The maximum density of 3x10¹⁶cm^-3 averages over the plasma waveguide diameter is found 8 cm apart from the PA. The stream density varies considerably along the plasma guide axis. The importance of the external magnetic field for plasma confinement and stabilization is shown. The optimum mode of operation of the coaxial PA is determined