Overview of the SIR-related event beginning on DOY 320 of 2018. Top three panels: energetic proton enhancements extending for almost four days. Panels 4 and 5: plasma conditions during this period as measured by the Solar Wind Electrons Alphas and Protons (SWEAP) instrument (Kasper et al. 2016); the associated compression region passing over the spacecraft near the beginning of DOY 319 is highlighted in yellow. Bottom panel: magnetic field as measured by the FIELDS instrument (Bale et al. 2016) in RTN (radial, tangential, normal) coordinates (see Fränz & Harper 2002), showing a highly radial field over this time period. Dotted red lines indicate the divisions between periods used for spectral analysis. The EPI-Lo, plasma, and magnetic field data are averaged over 15-min intervals, while the EPI-Hi data is hourly. No background subtraction has been applied to the data shown here.