1. The problem statement, all variables and given/known data Hi! I have trouble with calculating the upward and downward plasma speeds. I have the necessary data and an equation that is useful (I think), but I'm stuck. 2. Relevant equations The shock jump number Zs=3 in this case , and I've calculated the shock wave speed (555 km/s), which was calculated from the plasma density. The densities are n1=30 cm^-3 and n2=90 cm^-3 if you want to know. And now, I need the upstream and downstream plasma speeds. 3. The attempt at a solution I know that one equation that can be used is: u'1/u'2==B2/B1=n2/n1Zs Here, u'1 is the upward speed and u'2 the downward. But this doesn't give me any solutions because we have two unknowns .I know that the answers should be -285 km/s and -95 km/s respectively. I have data for the magnetic fields and proton temperatures. Can someone please help me?