Answer
$i=6.3 \times 10^8 \mathrm{~A} .$
Work Step by Step
From $\mu=i A=i \pi R_e^2$ we get
$$
i=\frac{\mu}{\pi R_e^2}=\frac{8.0 \times 10^{22} \mathrm{~J} / \mathrm{T}}{\pi\left(6.37 \times 10^6 \mathrm{~m}\right)^2}\\=6.3 \times 10^8 \mathrm{~A} .
$$
