\(E=100 \frac{ V }{ m } \quad R=6400 \,km\)
By Gauss law
\(E A=\frac{q}{\varepsilon_0} \Rightarrow q=E A \varepsilon_0\)
\(\Rightarrow q=200\left(4 \pi\left(6400 \times 10^3\right)^2\right) \times 8.85 \times 10^{-12}\)
\(\Rightarrow q=4.55 \times 10^5 \,C\)