The discussion focuses on the concept of polarization in electromagnetic (EM) waves, particularly in the context of electrodynamics. Participants explore the relationship between the electric and magnetic fields, the definition of polarization, and the implications of changes in the direction of the electric field on polarization.
Participants generally agree on the definition of polarization and the relationship between the electric and magnetic fields, but there remains some disagreement about the implications of polarization related to the magnetic field and the reasons for the convention of using the electric field.
Some statements reflect assumptions about the nature of polarization and the conventions used in electrodynamics, which may not be universally accepted or may depend on specific contexts.
how the polarization will affect by change in the direction of electric field?Born2bwire said:The electric and magnetic fields are always normal to each other for an electromagnetic wave. In a source-free homogeneous region of space, the electromagnetic waves can only be transverse waves. This means that the electric and magnetic field vectors are both normal to the direction of propagation. So, if we specify the vector direction of the electric field and propagation, then we have implicitly specified the direction of the magnetic field. By convention, we generally choose the electric field as the direction of reference for polarization.
Electric and magnetic fields are both vector fields. Not only do they have a magnitude and phase associated with each point in space, but they also have a direction. This direction is related to the direction that a test charge would travel from the force induced by the fields. For example, the Lorentz force on a test charge due to the electric field is simply
[tex]\mathbf{F} = q\mathbf{E}[/tex]
So that is why there is a direction associated with the fields (the relationship with the magnetic field is a bit more complicated, the cross product of the particle's velocity and magnetic field).
So the polarization of the electromagnetic wave is a way of describing the orientation of the electric field vector component of the wave as the wave propagates through space and time.
What do you mean? The polarization is the direction of the electric field.astro2cosmos said:how the polarization will affect by change in the direction of electric field?
astro2cosmos said:i read this "in electrodynamics, polarization characterizes em waves, such as light, by specifying the direction of the wave's electric field" in a book.
i really didn't get it clear & does the magnetic filed nothing to do with polarization?
jtbell said:In an EM wave the E and B fields are always at right angles to each other, so when you specify the direction of one, it automatically determines the direction of the other. We could use either one as the "polarization direction", but by convention we use the E field, to be consistent.
Yes, if the wave is polarized then both the magnetic and electric fields are polarized.astro2cosmos said:is there any polarization is generated by magnetic field ? likewise electric field.
As jtbell said, it is by convention. By widespread agreement, the electric field is used to specify the polarization direction. If you are told what that direction is, then you know the direction of both the electric and magnetic fields.& why polarization is only cause of eletric field?