Animation showing the magnetic fields generated around a conducting wire and a coil of wire (solenoid). Within a single wire, the right-hand rule applies. The right-hand rule is a mnemonic used to visualise the field. If the thumb of the right hand points in the same direction as the conventional current (positive to negative), then the curled fingers point in the direction of the magnetic field around the wire (north to south). When the wire is coiled into a spiral tube, it is called a solenoid, and has a field similar to that of a bar magnet. A right-hand rule still applies: when the fingers are coiled in the direction of the current, the thumb points to the north pole of the solenoid.