OMNI2 solar wind parameters, geomagnetic indices, and neutron monitor data for a two solar rotation period in December 1963–February 1964. The panels show: the magnetic field intensity and polar and azimuthal angles (GSE coordinates), solar wind proton temperature (not available for this period), and expected temperature (red graph; see Richardson & Cane 1995 for further details), density, and speed, the geomagnetic αα, Kp × 10, and Dst indices, the Thule neutron monitor counting rate (pressure-corrected) and our assessment of the solar wind structure type, indicated at the beginning of the structure interval, where 2 is a high-speed stream, 3 is slow solar wind, and 0 indicates that the structure type is unclear. Gray shading indicates a series of corotating high-speed streams. Vertical green lines indicate times of SSCs, typically associated during this interval with CIRs.