Authors: C. J. Farrugia (Space Science Center, University of New Hampshire, Durham, NH 03824), B. J. Vasquez (Space Science Center, University of New Hampshire, Durham, NH 03824), N. Lugaz (Space Science Center, University of New Hampshire, Durham, NH 03824), N. A. Al-Haddad (Space Science Center, University of New Hampshire, Durham, NH 03824), I. G. Richardson (NASA Goddard Space Flight Center, Heliophysics Science Division, Greenbelt, MD 20771, Department of Astronomy, University of Maryland, College Park 29742, MD), E. E. Davies (Austrian Space Weather Office, GeoSphere Austria, 8020 Graz, Austria), R. M. Winslow (Space Science Center, University of New Hampshire, Durham, NH 03824), B. Zhuang (Space Science Center, University of New Hampshire, Durham, NH 03824), C. Scolini (Space Science Center, University of New Hampshire, Durham, NH 03824), R. B. Torbert (Space Science Center, University of New Hampshire, Durham, NH 03824), L. B. Wilson III (NASA Goddard Space Flight Center, Heliophysics Science Division, Greenbelt, 20771, MD), F. Regnault (Space Science Center, University of New Hampshire, Durham, NH 03824), A. Rogers (Los Alamos National Laboratory, Los Alamos, NM), A. B. Galvin (Space Science Center, University of New Hampshire, Durham, NH 03824), W. Yu (Space Science Center, University of New Hampshire, Durham, NH 03824)

On April 19-20, 2020 a solar ejection was seen by spacecraft in a radial alignment that included
Solar Orbiter and Wind. The ejection contained a magnetic flux rope where magnetic field and plasma parameters  were well correlated between spacecraft. This structure is called the “Unperturbed Magnetic Flux Rope” (UMFR).  Ahead of the UMFR is a portion of the ejection (not sheath), that is referred to as “UpStream” (US).  We focus on US and inquire why the correlation is so much weaker there.  Specifically, we analyze data collected by Solar Orbiter at 0.81~au and Wind at L1. We show that a plausible cause for the lack of coherence in the US is a combination of front erosion and internal reconnection occurring there. Front erosion is inferred from an analysis of azimuthal magnetic flux balance in the UMFR. In the present case, we contend that the source of the eroded field lines is US, rather than the UMFR.  The presence of erosion is supported further by a direct comparison of the magnetic field data at both spacecraft which shows, in particular, a massive shrinkage of the front portion of the US. Internal reconnection is also happening at thin current sheets inside the US. Strong non-radial flows are reconfiguring the structure. As a result of these reconnection processes, a whole section of the  US is disrupted and field lines move down the flanks of the ejection and out of view of Wind.