The unusual signatures at and near 2018 UT (Wind in situ observations) of the travelling, fast forward interplanetary shock on September 25, 2001

We show that at 2018 UT on September 25, 2001, a velocity discontinuity of [-300, -200, -200] kms-1 (in GSE coordinates) passes Wind. However, the downstream shock candidate region appears to be far from thermal equilibrium. Henceforth it is our purpose to show that it is not a shock discontinuity amenable to the Rankine-Hugoniot based techniques. A possible shock related thermalization (at Wind) appears approximately 90 seconds later, at 2019:31UT, behind a magnetic hole showing a large rotational discontinuity. Timing using Wind and other spacecraft located tens to hundreds of earth radii apart allows the preliminary assessment of an overall shock normal. In the context of Sun-Earth connections, the disturbance appears related to the Sept 24,1030UT halo-CME [EIT observed a CME starting in AR9632 located at [S18; E27] at 09:12 UT], which was moving at 2240 kms-1 in the plane of the sky. In most events we put special value on the identification of the plasma density by using the electron plasma thermal line. However, there is a loss of detection of the plasma line between 2010 and 2016 UT. This shock is important, because strong particle and wave intensities appear to be associated with it. Candidate compressional waves are identified upstream of the shock. Their presence suggests that they are an additional source of turbulence. This is so, because the compressional waves are likely being created by the shock accelerated particles and subsequently overtaken by the shock, probably, in an almost continuous process.