Longitudional electro magnetic waves and linear polarisation

In summary: Electromagnetic radiation is said to be linearly polarized if the electric field of each wave is confined to some plane along the direction of propagation.[1] A wave with any other polarization state is an inhomogeneous wave, which is a superposition of plane waves with different polarizations. Linear polarization is often used to describe the polarization direction of electromagnetic waves, which are radiated by electrically charged objects. This polarization direction corresponds to the direction of the electric field vector. In summary, linearly polarized waves, as defined in antenna theory, are different from longitudinal EM waves, which can exist under certain circumstances but are not found in free space or homogeneous media.
  • #1
h3x3n
15
0
Hello,
Are longitudinal EM waves ( I know they exist) any different from linearly polarised waves we learn about in antennae theory

Just to be clear http://www.antenna-theory.com/basics/polarization.php defines linear polarisation pretty clearly in the context i am talking about
 
Physics news on Phys.org
  • #2
yes.

As your link indicates, polarized waves are transverse waves', Longitudional waves are not. EM waves are transverse except under special constraints:

[Maxwell's equations lead to the prediction of electromagnetic waves in a vacuum, which are transverse (in that the electric fields and magnetic fields vary perpendicularly to the direction of propagation).[2] However, waves can exist in plasmas or confined spaces, called plasma waves, which can be longitudinal, transverse, or a mixture of both.[2][3] .....
After Heaviside's attempts to generalize Maxwell's equations, Heaviside came to the conclusion that electromagnetic waves were not to be found as longitudinal waves in "free space" or homogeneous media.[5] But Maxwell's equations do lead to the appearance of longitudinal waves under some circumstances, for example, in plasma waves or guided waves...QUOTE]

http://en.wikipedia.org/wiki/Longitudinal_electromagnetic_wave#Electromagnetic

In electrodynamics, linear polarization or plane polarization of electromagnetic radiation is a confinement of the electric field vector or magnetic field vector to a given plane along the direction of propagation.
 

1. What are longitudinal electromagnetic waves?

Longitudinal electromagnetic waves are a type of electromagnetic radiation that travels in a direction parallel to the oscillation of the electric and magnetic fields. They are also known as Hertzian waves and are characterized by their ability to travel through a vacuum.

2. How are longitudinal electromagnetic waves different from transverse waves?

Unlike transverse waves, which have perpendicular oscillations of the electric and magnetic fields, longitudinal electromagnetic waves have parallel oscillations. This means that the electric field and magnetic field are both in the same direction of propagation for longitudinal waves.

3. What is linear polarization in electromagnetic waves?

Linear polarization is a property of electromagnetic waves that describes the orientation of the electric field. In linearly polarized waves, the electric field oscillates in a single plane, while in unpolarized waves, the electric field oscillates in all directions perpendicular to the direction of propagation.

4. How is linear polarization achieved in electromagnetic waves?

Linear polarization can be achieved by filtering out all but one direction of the electric field in unpolarized waves, or by using an antenna or other device to restrict the oscillations of the electric field to a single plane. This results in a wave that is linearly polarized.

5. What are some applications of longitudinal electromagnetic waves and linear polarization?

Longitudinal electromagnetic waves and linear polarization have many practical applications, including in wireless communication, radar technology, and medical imaging. They are also used in technologies such as radio and television broadcasting, satellite communication, and microwave ovens.

Similar threads

Replies
7
Views
2K
Replies
4
Views
981
Replies
2
Views
2K
  • Quantum Physics
Replies
3
Views
709
Replies
2
Views
1K
  • Atomic and Condensed Matter
Replies
4
Views
838
Replies
6
Views
3K
  • Electromagnetism
Replies
4
Views
1K
Replies
3
Views
732
  • STEM Academic Advising
Replies
14
Views
514
Back
Top