The Confinement Radius of a Cosmic Ray (Galactic vs. Extra-galactic)

[mjda]

If we want to show whether or not a specific Cosmic Ray particle is confined to our galaxy we must use the Larmor radius (relativistic version),

r = γmc / qB

Considering a 10^14 eV proton and assuming the galactic magnetic field strength is 10^−11 T, show that the particle is confined to the Milky Way (radius 15^15 kpc).

How can we use the Larmor radius to prove that the particle is in fact confined to the Milky Way?

 

[mfb]

Just plug in the values?
If the path of a particle has a curvature radius much smaller than the galaxy it won’t leave it, or at least will leave it only much later and severely scattered.

Something went wrong with the radius of the Milky Way.