Processes of the solar-wind/magnetosphere interaction can be monitored by magnetic records on the ground from the worldwide array of stations. However, a serious drawback of the analysis of ground-based magnetograms is the inevitable variation of the magnetic response due to continual changes of the station location. An ideal, but impossible, solution of this difficulty, that will help to discriminate temporal and spatial variations, would be the deployment of a ``stationary'' in situ observatory with a fixed position in the solar-magnetospheric coordinate system. However, the desired result can be obtained with the proposed technique of ``virtual magnetograms'' VMs. This technique has been implemented for key magnetospheric domains midnight auroral and noon cusp regions as an additional tool for monitoring the response of the geomagnetic field to solar wind and interplanetary magnetic field forcing. A VM is reconstructed by 2D gridding and interpolation of 1-min magnetograms from $>200$ magnetic stations distributed worldwide. VMs have been produced for the period since 1994 up to the current year for both Northern and Southern hemispheres. A wide range of space physics studies, such as the solar wind-magnetosphere interaction, dayside-nightside coupling, etc. will benefit from the introduction of the VMs. The VMs for the dayside cusp and midnight auroral regions in both hemispheres, as well as simultaneous interplanetary parameters solar wind density, electric field $E_y$ and geomagnetic indices $AE$, SYMH, and PC, are combined in one plot. These quick-look plots and corresponding digital files are freely available via the web site \hrefhttp://vm.gcras.ruhttp://vm.gcras.ru for all interested researchers for testing and validation. Here we present examples of VMs for the following phenomena: a sawtooth event, modulation of the dayside cusp by IMF variations, and coupling between the dayside cusp ULF activity and substorms. VM database may make the selection of events for subsequent in-depth analysis much easier.
Solar wind--magnetosphere interaction, dayside-nightside coupling, sawtooth events, substorm, virtual magnetograms, ULF waves
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