Hopefully this will help , if not confuse some moreÂÂ

A distortion in the fabric of space, aether, or whatever we want to call empty space, is called a field. ÂÂ
Early on in the discovery of electrostatic/magnetic attractions, it was apparent that two objects exerted forces on each other AT A DISTANCE.
Well, they didn't like this concept of ACTION AT A DISTANCE, and this distortion, or field concept was proposed as more intuitive.
Now, There are two categories of fields.
1) VECTOR FIELDS   (e.g. electric, magnetic, gavitic, flow, strain, stress,etc.)
2) SCALAR FIELDS  (e.g. temperature)
What is the difference?
With vector fields, at any point in space we can assign a 1) VALUE or MAGNITUDE, and 2) a DIRECTION.
Scalar fields only have the first part, A VALUE.  For example, Temperature in a room has only a value at a particular point, we can't say it has any direction, however, heat FLOW, is a VECTOR field, and at a particular point in the room heat flows in a particular DIRECTION.
Now, with pretty much any scalar field there can be associated a VECTOR field.  Pressure distribution in a 3D space is a SCALR field, but variations of pressure can be expressed as the GRADIENT of that SCALAR field, and it's now becomes a VECTOR field, since, once again, a DIRECTION is now associated with it (this is called taking the GRADIENT of the scalar field).
Anyway, That's what the scientific comunity understands by scalar fields, it's not something bogus.
So, can there be scalar fields in electromagnetic theory?
Well, charge density is a scalar field, does charge (an electron) have a direction? No, so a charge distribution in a wire in space (charged air) is a scalar field.
Now, if there are fields, there must be waves.  So can there be waves supported by VECTOR fields, yes EM waves,ÂÂ
Can there be SCALAR waves? well, yes and no, you need a SCALAR field alongside a VECTOR field. ÂÂ
For example: AUDIO waves are due to SCALAR pressure field distributions, and the VECTOR field of air flow due to that SCALAR field. They go hand in hand. So in a sense you do have a SCALAR wave that has moved, but we need to understand what's involved.
EM