Near Earth, the density of protons in the solar wind (a stream of particles from the Sun) is 8.90 cm-3 and their speed is about 490 km/s. (a) Find the current density of these protons. (b) If Earth's magnetic field did not deflect the protons, what total current would Earth receive? For part a I used Current density (J) = nqv, we know q and v. I tried finding n(number of protons) by finding the volume by m/density. Then using Avogadro's number/volume to get n. For part b I said that the Current would just me Part a answer multiplied by the cross sectional area, but i did not get part a right.