How can the current density and magnetic field affect Earth's total current?

[juggalomike]

Homework Statement

Near Earth, the density of protons in the solar wind (a stream of particles from the Sun) is 8.60 cm-3 and their speed is about 490 km/s.
(a) Find the current density of these protons.
6.74E-7 A/m^2
(b) If Earth's magnetic field did not deflect the protons, what total current would Earth receive?

Homework Equations

J=I/A

The Attempt at a Solution

Using the equation above i used J*A=I, the problem is the area is used for the Earth is apparently wrong(as i know my J is correct), so i looked online for it again and found 2 more answers(all the same numbers but to different powers of 10). Anyone know the actual surface area of the earth?(i would try plugging on all the ones i find but I am limited on attempts for this question and i already used 2/5 of my tries)

 

[ehild]

All those protons will reach the Earth which are in the beam of cross-section equal to that of the Earth.

ehild

 

[Lok]

What surface area do you need, the sphere or crossection?

 

[juggalomike]

What surface area do you need, the sphere or crossection?

id assume surface, what is corssection?

 

[Lok]

id assume surface, what is corssection?

There is the surface of the earth, which is somewhat a sphere or it's crossssection or the surface the electrons hit, so the area of a circle with the radius of earth. Which one have you been looking for and which one do you need?