If a solenoid oriented on the z axis is carrying a steady current, I if will produce a constant B field inside of the solenoid. A charged particle with initial velocity perpendicular to the z axis will undergo cyclotron motion within the solenoid at a constant radius, r. What are the electric and magnetic fields as seen from the particles reference frame. I think that the B field will remain the same as seen from the lab frame. is this correct? I don't see any reason why the B field would change.