Can light travel as a longitudinal wave?

Click For Summary
SUMMARY

The discussion centers on the nature of electromagnetic (EM) waves, specifically addressing the misconception that light can travel as a longitudinal wave. Participants clarify that oscillating charges in a vacuum create near-field effects, which do not constitute true EM waves. EM waves are definitively transverse, characterized by two polarization states, and any claim of longitudinal behavior must demonstrate three polarization states to be valid.

PREREQUISITES
  • Understanding of electromagnetic wave theory
  • Familiarity with polarization states of waves
  • Knowledge of charge oscillation in a vacuum
  • Basic principles of near-field and far-field effects
NEXT STEPS
  • Research the properties of transverse waves in electromagnetic theory
  • Study the concept of polarization states in EM waves
  • Explore the differences between near-field and far-field electromagnetic effects
  • Investigate the implications of longitudinal waves in different physical contexts
USEFUL FOR

Physicists, electrical engineers, and students of electromagnetism seeking to deepen their understanding of wave propagation and polarization in electromagnetic theory.

k9b4
Messages
109
Reaction score
2
If i have a charge in a vacuum, and I oscillate it at some frequency in x direction, other charges along the x direction will be caused to oscillate in the x direction.

So why was I always taught that the direction of oscillation is always perpendicular to the direction of travel for EM waves?
 
Science news on Phys.org
Charges in motion constitute an electric current.
 
k9b4 said:
If i have a charge in a vacuum, and I oscillate it at some frequency in x direction, other charges along the x direction will be caused to oscillate in the x direction.

So why was I always taught that the direction of oscillation is always perpendicular to the direction of travel for EM waves?
What you describe is only a near field effect, so it isn't properly an EM wave at all.

EM waves are transverse because they have two polarization states. If you wish to make an argument that they can be longitudinal also then you must show that they have 3 polarization states.
 
  • Like
Likes   Reactions: Rolliet and davenn

Similar threads

  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 6 ·
Replies
6
Views
14K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 41 ·
2
Replies
41
Views
5K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
7
Views
2K
  • · Replies 17 ·
Replies
17
Views
4K