Plasma parameters at Earth (OMNI), compared with the results of HelioCast with three different values for the parameter d. Magnetic field components X and Y (GSE coordinates) are well-reproduced. The black line in the top panel is a one-day running average of the B _X data. HSSs are reproduced with varying amplitudes depending on d in the third, velocity panel. The bottom panel shows the density variations, which are best reproduced for d = 10°.