Helios 2 at 0.3 AU. Panel a: bulk speed, V_sw (lower plot), and the v − b correlation coefficient at 1 h scale, C_vb (upper plot). Panels b and c: scatter plots of T_R (as derived with Eq. (1)) and θ_BR for an interval of slow wind (left) and fast wind (right), respectively, using data from NASA website CDAWeb (https://cdaweb.sci.gsfc.nasa.gov), indicated as original. Panels d and e: analogous to panels b and c, respectively, for data from the Space Sciences Laboratory University of California (Berkeley) dataset (http://helios-data.ssl.berkeley.edu/data/), indicated as reprocessed. We show also the scatter plots of the total temperature T vs. θ_BR referring to reprocessed data in panels f and g. Panels b–g: we report also the value of the linear correlation coefficient, C, between T_R (or T) and θ_BR, in the zoomed time intervals.