Figure 5: Solar wind parameters observed at STEREO A.

From top to bottom, the panels show the proton density (a), bulk speed (b), proton temperature (c), magnetic field strength (d) and components (e–g), and D_st index (h), respectively. The shaded regions indicate the ICME intervals, and the vertical dashed line marks the associated shock. The red curve in panel a represents the number density (multiplied by a factor of 5) of electrons with energies above 45 eV. Speeds derived from O⁺⁶ and O⁺⁷ fits are also shown in panel b and are consistent with the bulk speeds calculated from proton distributions. The dotted curve in panel c denotes the expected proton temperature from the observed speed. The D_st values in panel h are estimated using the formulae of Burton et al.³³ (red) and O'Brien and McPherron³⁴ (black), respectively.