This International Standard describes the main magnetospheric large-scale current systems and the magnetic field in the earth's magnetosphere and provides the main requirements for a model of the magnetospheric magnetic field. Ionospheric currents are not considered in this International Standard. Annex A of this International Standard gives a worked example of the model and establishes the parameters of magnetospheric large-scale current systems that change according to conditions in the space environment. This International Standard can be used to develop new models of the magnetospheric magnetic field. Such models are useful in investigating the physical processes in the earth's magnetosphere as well as in calculations associated with developing, testing and estimating the results of exploitation of spacecrafts and other equipment operating in the space environment. The main goals of standardizing the concepts of the earth's magnetospheric magnetic field are to provide — an unambiguous presentation of the magnetic field in the earth's magnetosphere; — compatibility for the results of the interpretation and analysis of space experiments; — less labour-intensive calculations of the magnetic field of magnetospheric currents in space at geocentric distances of 1,0 to 6,6 earth radii, RE; — the most reliable calculations of all elements of the geomagnetic field in the space environment. The magnetic field model presented in Annex A of this International Standard can be used to predict the radiation conditions in space, including the periods of intense magnetic disturbances (magnetic storms), when developing systems of spacecraft magnetic orientation and when forecasting the influence of magnetic disturbances on transcontinental piping and power transmission lines.