Current density of protons in solar wind at Earth's orbit

[flash525]

Near earth, the density of protons in the solar wind is 10.0cm^-3, and their speed is 691 km/s.
a) find current density of these protons
b) what current in amperes does Earth receive




a. To find the current density I need to multiply (nLA)e
then after i get I divide it by A

The Attempt at a Solution

To find the current density I need to multiply (nLA)e

do i need to convert 10.0 protons cm^-3 to 10000000m^-3 because i tried that and it didnt work?
I guess my main question is do i have the conversions right:
v= 691000 m/s
n = 1 E7
e= 1.6E-19
the final answer i got was 1.11 E-7 (is this answer maybe negative?)

 

[member 553083]

b. To find the current in Amperes that Earth recieves I multiply the current density by the area:1.11E-7 * 4*π*(6.371E6)^2 = 8.82E12 amperes