Evolution of the heliospheric plasma sheet observed in situ by 3 spacecraft over 4 solar rotations

We present in situ observations of the heliospheric plasma sheet (HPS) from 3 observatories (STEREO-A, STEREO-B, and WIND) over 4 solar rotations: Carrington rotations (CR) 2054 through 2057. At least one interplanetary coronal mass ejection (ICME) occurred during CR 2056, which leads to reorganization of the HPS from its previous quasi-stationary structure. The HPS crossings were identified using criteria including reversal of the interplanetary magnetic field, increased proton density, and local minima in proton entropy and in the alpha to proton density ratio. We also find an enhancement of the average iron charge state at the HPS.