Visualization of the results of the 3DCORE flux rope model fitted to the Solar Orbiter MAG observations, shown at the time of the onset of the Forbush decrease at Earth. The reconstructed 3D flux rope structure is shown: (a) looking down from the solar north pole onto the solar equatorial plane, (b) in a frontal view along the Sun–Earth line, and (c) in a side view at a 75 degree angle, the longitude of STEREO–A to Earth. A flux rope field line is highlighted as a solid blue line. Panels d and e: in situ magnetic field data from Solar Orbiter and Wind at Earth/L1 compared to the GCR variation as a percentage drop in the amplitude measured by EPD/HET and CRaTER. The Wind magnetic field components are given here in Heliocentric Earth Ecliptic (HEE) coordinates, as in Fig. 5. The 3DCORE modeled magnetic field is overplotted in panel d and propagated to Earth as shown in (e). An animation of this figure is available as an online movie.