A magnetic field is a region of space around a magnet or electric current where magnetic forces can be observed. It is produced by the movement of electrically charged particles, such as electrons or protons.
When a stream of protons, which have a positive charge, moves through a magnetic field, it creates a force known as the Lorentz force. This force causes the protons to curve in their path, creating a circular motion and thus, a magnetic field.
The strength of the magnetic field created by a stream of protons depends on the speed and density of the protons, as well as the strength of the external magnetic field they are passing through.
The direction of the magnetic field from a stream of protons can be determined by the right-hand rule. If you point your right thumb in the direction of the proton's velocity, the direction of the magnetic field can be determined by the curl of your fingers.
The magnetic field created by a stream of protons has various applications in scientific research, such as in particle accelerators and magnetic confinement fusion reactors. It is also used in medical imaging techniques, such as magnetic resonance imaging (MRI), to create detailed images of the body's tissues and organs.