Comment by Irrasible on 26/12/2023 at 22:50 UTC

0 upvotes, 1 direct replies (showing 1)

View submission: Two questions about light waves

Forget photons. They do not have a magnetic field or an electric field. They are responsible for the actions that used to be attributed to the classical electromagnetic field.

As for the classical EM field, it is easier to answer your question by considering the potentials.

That leaves *gradient* {φ} as a term that might cause **E** to not be perpendicular to **H**.

The scaler electric potential, φ, is determined entirely by charge distributions. However, the universe is or appears to be essentially neutral. So, out in free space, far away from matter, φ~0 and *gradient* {φ} →0. Thus, out in free space, **E**���**H**=0.

So, when can *gradient* {φ} ≠ 0? When you are near stuff. Near a dipole antenna, *gradient* {φ} can be very strong. It can also be non-zero in or near a waveguide.

Replies

Comment by Jeff-Root at 27/12/2023 at 13:59 UTC*

2 upvotes, 1 direct replies

At the time I'm posting this, your post has -1 point, but no explanation of why it was downvoted, so I'm not certain whether to take it seriously. If there is anything wrong with **Irrasible Engineering**'s reply, please explain what that is. For now, I have to take it seriously. Possibly it was only downvoted because it uses math beyond my apparent level of comprehension.

The paper linked earlier by **agaminon 22** was way above my head. What you say here is just a little above my head. I am not competent at calculus or its language or terminology. But it looks completely logical.

I can't forget photons because photons are what I'm trying to understand.

However, you tell me that photons do not have a magnetic or electric field. That makes sense if my understanding of what a field is is flawed or incomplete, and it is certainly very incomplete.

Can you explain in simple terms what the difference is between a field strength and a potential? That is a question I hoped to ask at some future time, but it looks like I need to ask now. I can imagine that a fully accurate explanation would be way beyond what I can understand, and that these are probably relativistic concepts, which complicates them terribly. But you did say "classical".

Please let me start out by asking the most basic questions: What is the function of the leading dots on the **E** and **H** ? And what does **A** represent? I do not know how to look those up in a search.

I will return to this after I've watched the video linked by **James_James_85**

Thank you!