Right-hand rule#Direction associated with a rotation

The corkscrew rule, alternatively known as rights - fist rule, right - thumb - rule [NB 1], screw or Umfassungsregel, is a rule of thumb to determine the ideological direction of the magnetic field generated by a current-carrying conductor. The common name is also the corkscrew rule as right-hand- rule, however, is not clear, since this is also a synonym for the three- finger rule of the right hand.

Has to be considered also that at any " rights Fist " or " Right - thumb - rule" complementary " Left - fist rule" or " Left - thumb - rule" for the reverse flow direction ( ie the direction of flow of negative charge carriers) can be formulated.

Corkscrew rule, screw rule

If one turns a corkscrew so that it is in the conventional direction of current or, ie screwed forward by the electric positive to the negative pole, so that its rotational direction is the direction of the magnetic field lines created by current flow, whereby it is assumed that this direction of rotation which is always in conventional corkscrews to right, clockwise.

Analog is postulated in formulating the rule as " Maxwell's screw rule " that if you screw a screw into conventional or technical current direction forward, thereby indicating its direction of rotation, the direction of magnetic field lines generated by the current flow, it being understood here also implied that one doing a screw with right thread used.

Rights - fist rule, right - thumb rule, Umfassungsregel

If the conductor with your right hand covers so that the splayed thumb or the conventional direction of current, ie the electric plus to the negative pole, indicating that show the curved finger to the direction of the resulting magnetic field.

For a current loop, for example, in the coil of an electromagnet (see below), therefore the following applies:

If the bobbin with your right hand so includes that the fingers are curved in the direction of the current technical direction, shows the splayed thumb in the direction of forming the magnetic north pole.

As indicated, the direction of current while the actual movement direction of the conduction electrons is opposite. If one replaces the other hand, in the above formulation, the right hand through the left, one obtains for a rule that takes into account the real direction of motion of the electrons - therefore referred to as left - thumb - or Left - thumb - rule, this rule sits opposite but the traditional rights fist or right - thumb rule only very slowly, especially in newer sources through.

Basis of the rule is that Maxwell's equation or its integral form

Determining direction of the Lorentz force

The current in a conductor produces around the conductor a magnetic field whose sense of direction according to the right thumb - rule is as follows: If the current flows in the direction of the thumb by the covered conductor ( in the picture left to rear ) that forms around these a magnetic field in the direction ( in the picture on the right clockwise) curved finger. In conjunction with an external cross - Head looking - magnetic field arises on one side of the head, a reinforced, on the other other hand, a weakened magnetic field. Field lines of the same direction but repel each other, it affects the Lorentz force in the direction of increasing the weaker magnetic field ( in the picture to the left).

Applications of this principle are electrodynamic drives of all types:

• Electric motors
• Voice coil speakers
• Galvanometer, Drehspulmesswerke

But even free-flying through a magnetic field, electric charges experience a force in the described manner and direction that distracts them from their original path. As a result of the deflection, however, also changes continuously the direction of the Lorentz force: they always acts perpendicular to the direction of motion, so as a centripetal force, which means that moving charges, which are deflected by means of a homogeneous magnetic field, while, unlike for example, upon deflection of a homogeneous electric field, always describe a circular path.

This method is used in the magnetic deflection of charged particles moving:

• Deflection of the electrons in the cathode ray tube
• Curvature of the path of charged particles in a cloud chamber
• Distraction and temporary non -free storage of elementary particles that have been accelerated by particle accelerators, storage rings in magnetically stabilized
• Sorting of ions on the type and mass in the mass spectrometry

Determine the polarity of an electromagnet

An electromagnet consists of many, co -carrying conductors of electricity in an open iron core. All the winding cross-section filled Managers in each have one they ambient magnetic field whose field lines because the current directions of all the windings are equal, all run in the same direction and add up thus to the entire winding cross section total circumferential field. Exit point of this field from the iron core is finally the one coil end, where according to the right thumb - rule is (or in the reverse flow direction according to the left - fist rule) the magnetic north pole of the electromagnet, re-entry point of the field lines in the iron core the one coil end, where the magnetic south pole forms.

That the oppositely directed field lines respectively adjacent coil windings cancel each other out, they have, as soon as a current flows through it, the desire each other to get closer to and on the other hand due to the mutual repulsion of the parallel field lines inside the coil lumen ( the internal cross section ) of the coil to. enlarge Thus, current -carrying coils have on the one hand the desire to expand transversely to the longitudinal direction in the longitudinal direction, however, to contract (the principle of " Rogetschen spiral ").

Electromagnets have many uses, from train and holding magnet electric motors to the distraction of moving elementary particles and ions in particle accelerators and mass spectrometers, as well as for medical diagnosis using magnetic resonance imaging.