Fig. 49.

Solar wind parameters, the density of the suprathermal proton tail, and the spectral index of the ST tail for the extreme quiet conditions in the solar wind during 2009. Possible shocks are marked with thin vertical lines; the compression ratio across the shock is also shown. The shaded regions indicate time periods during which spectra shown in Fig. 48 were taken. Image reproduced with permission from Fisk and Gloeckler (2012), copyright by Springer