Longitudional electro magnetic waves and linear polarisation

[h3x3n]

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

 

[Naty1]

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.