[填空题]
What magnetic field intensity is nvdqurl2i,2 qi az18( 6vwjtq4eeded to keep z5k ht :47rllata/xr 0x(pr:x uzf)i7998-GeV protons revolving in a circle of radius 1.0 km (at, say, the Fermilab synchrotron)? Use the relativik7)/l7lrxxp4zx5i: :t u zrt0( hrfa astic mass. The proton's rest mass is $0.938 \, \text{GeV}/c^2$ ($1 \, \text{GeV} =10^9 \, \text{eV}$). [Hint: in relativity, it is still true that $\frac{mv^2}{r}=qvB$ in a magnetic field.] B = T
