# magentic field parralel an normal on planes

#### yef smith

Joined Aug 2, 2020
293
Hello,given the photo bellow the magnetic field is shown in red circle.
from the manual shown bellow they say:
"Since the magnetic field in Figure 1 is normal to the YZ plane then its tangential component will be zero in the YZ plane."

The magnetic field is in circles, in some section its nornal to YZ plane in some section its not.
Why they say its always normal to the YZ plane?

http://throberts.blogspot.com/2016/08/notes-on-symmetry-using-cst-microwave.html

#### nsaspook

Joined Aug 27, 2009
8,909
I would think they would mean normal to the entirely transverse electric field pattern of 'vibration'.

#### yef smith

Joined Aug 2, 2020
293
Hello nsaspook, i am asking about the magnetic field.
What is a vibration?
IN your perspective this magnetic field.
to what planes its normal?
Thanks.

#### nsaspook

Joined Aug 27, 2009
8,909
For the TE01 mode, the electric fields are normal to the broad wall (blue field lines). The magnetic fields (red field lines) are normal to the narrow wall. In relation to the XYZ axis, the electric fields are parallel to the YZ plane and normal to the XZ plane. The magnetic field is normal to the YZ plane and parallel to the YX plane.

In TE mode the blue lines don't move in the direction of propagation, they oscillate 'vibrate' in transverse while the red lines 'magnetic fields' propagate longitudinally.

#### yef smith

Joined Aug 2, 2020
293
Hello,I have written blue arrows and red arrows.
if we look at the blue arrows then our magnetic field is normal to YZ,but if we look at the red arrows then its the other way around.
Why did you choose the blue arrow field line of the magnetic field?
Thanks.

#### nsaspook

Joined Aug 27, 2009
8,909
Last edited:

#### Tesla23

Joined May 10, 2009
488
Clearly that blog post is wrong, as seems to be noted in the comments below it.

My suggestion is that to learn this standard stuff like waveguide modes that you try restricting your searches to more reliable sources, e.g. add site:edu to your google search to search US universities. MIT, for example, has lots of good material.