This results in an easier and cleaner concept of how magnets interact. 1820 Hans Oersted found that electric current through a wire affects a compass as a magnet would and so electric current through a wire must produce a magnetic field. The fingers of the right hand will curl in the direction of the magnetic field if the thumb of the right hand is oriented in the same direction as the current. In fact physicists tend to visualize the source of magnetic fields in a magnet as being small current loops as the electron moves within the atoms of magnetic materials. But if you move along with the charges, you can't measure a magnetic field.
Magnetic fields arise only with relative movement between the charge and the observer.
Thus you can control the magnetic field as you want. This is called an iron core electromagnet. If the thumb is in the direction of the current and the fingers point along the direction of the magnetic field, the force will be directed away from the palm of the hand. So a moveable wire in a magnetic field will deflect accordingly in a magnetic field if a current flows through it. Van Allen Belts.