Magnetosphere and Auroral Oval Dynamics during February 27, 2023 Magnetic Storm

We discuss the reasons for the extreme compression of the magnetosphere during the storm on February 27, 2023, when the magnetopause crossed the geostationary orbit. At the same time, aurora was observed at middle latitudes. The global parameters of magnetospheric current systems were calculated from data on the parameters of the interplanetary medium and geomagnetic indices characterizing the evolution of the ring current and the westward auroral electrojet, using a paraboloid model of the magnetosphere. We have calculated the contributions of various current systems to the observed value of the \({{D}_{{st}}}\) index. The contribution of the tail current sheet is comparable with the contribution of the ring current for this storm. The calculated modelled field is compared with the data of the GOES-16, 18 magnetometers; the results are in good agreement with observations.