Magnetic Field

Magnetic field

A magnet produces a vector field, the magnetic field, at all points in the space around it.  

It can be defined by measuring the force the field exerts on a moving charged particle, such as an electron.  

The force (F) is equal to the charge (q) times the speed of the particle times the magnitude of the field (B), or F = q*v x B,

 where the direction of F is at right angles to both v and B as a result of the cross product.

a) Magnetic field lines

A magnetic field line can be thought of as consisting of lines of force. 

The forces of magnetic attraction and repulsion move along the lines of force.

b) Magnetic pole models

Geomagnetic models form the foundation of traditional, compass-based navigational systems. 

The primary world model is the International Geomagnetic Reference Field (IGRF), compiled from magnetic measurements 

collected by national observatories in many countries, as well as readings made from ships, airplanes, and satellites.

The Magnetic Field Strength is also called: Magnetic

Field Intensity or H-field or Magnetizing Force

Units of H are: Ampere per meter = A/m = A m—1

1- Magnetic pole model and the H-field

2- Amperian loop model and the B-field

c) Amperian loop modal

electric currents produce a magnetic field and Ampere discovered that electric currents attracted and repelled 

each other similar to magnets, it was natural to hypothesize that all magnetic fields are due to electric current loops. 

In this model developed by Ampere, the elementary magnetic dipole that makes up all magnets is a sufficiently small 

Amperian loop of current I. The dipole moment of this loop is m = I A where A is the area of the loop.

Magnetic field

A magnet produces a vector field, the magnetic field, at all points in the space around it. It can be defined by measuring the force the field exerts on a moving charged particle, such as an electron.  

Magnetic field lines

A magnetic field line can be thought of as consisting of lines of force. The forces of magnetic attraction and repulsion move along the lines of force.

Magnetic pole models

Geomagnetic models form the foundation of traditional, compass-based navigational systems. 

The primary world model is the International Geomagnetic Reference Field (IGRF), compiled from magnetic measurements 

collected by national observatories in many countries, as well as readings made from ships, airplanes, and satellites.

1- Magnetic pole model and the H-field

2- Amperian loop model and the B-field

Amperian loop modal

Electric currents produce a magnetic field and Ampere discovered that electric currents attracted and repelled each other similar to magnets, it was natural to hypothesize that all magnetic fields are due to electric current loops.