Right-hand Rule for a Moving Proton

• First, rotate your right wrist so you can point your fingers in the direction of the proton's velocity (green vector).
• Second, curl your fingers toward the unit vector r-hat (purple vector pointing from source to observation location).
• Third, stick out your thumb in the direction of the magnetic field at the observation location.
• Fourth, move your thumb to the observation location (if your own thumb is not detachable you may choose only to imagine this step).