Very high acceleration of charged particles at relativistic speeds. Synchroton RadiationOk. explain a pulsar next.
Very high acceleration of charged particles at relativistic speeds. Synchroton RadiationOk. explain a pulsar next.
So to make a very very very long story short, a DC current does not radiate energy.Current is not electrical energy, current is a rate, a changing frame of reference in space and time.
With a "changing magnetic field that will in turn create a changing electric field" what is actually changing? Magnetic and electric fields are aspects of one relativistic object. The source of the magnetic field, B, is also a source of an electric field, E. There is no cause and effect, there is only a coupled existence. In the relativistic point of view, the “magnetic field” is just an electrical field as experienced by (i.e. relative to) forces on other charged particles in the vicinity. Frame of reference separates the electric field and “magnetic” fields for the observer.
For EM radiation on the spinning battery we need discontinuously distributed charge under acceleration. IMO what we will mainly see are non-radiating reactive fields (like a generators induction fields) with very little EM radiation with the energy source from the rotation of charge. Don't assume that just because there is this changing EM field, it has to transmit energy 'far' away from the charged body.
Initially stationary, uniformly accelerated for a short period of time, and then stopped accelerating.
View attachment 261056
The EM wave is the 'kink'
I would say the spinning battery would work to radiate energy if it was modulated.It’s a very good theoretical model from distant observation.
Of course the model will evolve as we get closer to the object under observation. Pulsar surface gets update
For our spinning battery or dipole magnet theory, I would love to see the experiment and measurements. Even if some can guess the results without it. Always verify.
When you figure out your current vs voltage question, please let me know what happens first,I think there is some confusion as to what i mean when i say simultaneous.
I am not saying that current reaches it's highest point instantaneously. I am saying that current STARTS to flow as soon as voltage is applied. It is the start point, at t=0, that i am talking about, not 1ps later or 1us later although we could look at that too.
https://en.wikipedia.org/wiki/Nissan_PulsarOk. explain a pulsar next.
An interesting thought you bring upSo to make a very very very long story short, a DC current does not radiate energy.
Maxwell famous fourth equation added term.
Technically, no. You don't. Can energy be used to create a force? Yes.do you not need energy to create force ?
For a foot long battery the electrical length gives a wavelength for about 1GHz. For a reasonable RF radiator maybe 1/10 wavelength phase shift across space that's 100MHz but we'll use 1/1000 for 1MHz for an idea of the rate of change needed in the separated battery charges for retarded time EM radiation. The rotational speeds changes needed for dipole EM radiation would require a large amounts of KE for the tiny amounts of far-field energy EM produced.I would say the spinning battery would work to radiate energy if it was modulated.
It's interesting though to look at the unmodulated case also. There we would have circular symmetry for every electron in the package, at least on average. That would look like a whole bunch of turns of wire almost like a coil of wire except instead of a helix it would look like a lot of concentric circular paths. So i think that would constitute a DC current or a set of DC currents. Change the rotational speed however and we must see radiation (again Maxwell's fourth equation).
Oh sure, but it's all part of classical theoryFor a foot long battery the electrical length gives a wavelength for about 1GHz. For a reasonable RF radiator maybe 1/10 wavelength phase shift across space that's 100MHz but we'll use 1/1000 for 1MHz for an idea of the rate of change needed in the separated battery charges for retarded time EM radiation. The rotational speeds changes needed for dipole EM radiation would require a large amounts of KE for the tiny amounts of far-field energy EM produced.
https://en.wikipedia.org/wiki/Retarded_time
Oh i meant a DC current isolated in say deep space and if something comes near it it will surely radiate energy because there will be an acceleration of the object (assumed to have conductors) and we know that when coils of wire move through a static magnetic field energy is transferred.An interesting thought you bring up
" a DC current does not radiate energy "
a DC current generates a magnetic field me thinks,
and if Im another magnet, or ferrous, and I push up against the field
I experience a force against my movement,
do you not need energy to create force ?
Magnetism is not energy, ( not least different units of measurement ! )
not thought about it before
interesting,
Does this DC form a loop (completed closed circuit) or do you somehow have an isolated single straight wire in deep space and a current source on one side and a current sink on the other?Oh i meant a DC current isolated in say deep space and if something comes near it it will surely radiate energy because there will be an acceleration of the object (assumed to have conductors) and we know that when coils of wire move through a static magnetic field energy is transferred.
See my example about the two solar systems above (i think the preceding post).
Well i did not intend this thread to be about solving this it was really to show that there actually is no first or second that's why i keep saying "simultaneously".When you figure out your current vs voltage question, please let me know what happens first,
- Force or acceleration
- distance or time
- ...
I think either way although the straight wire segment is easiest to calculate the magnetic field of (from basic theory that is not from a pre-developed formula).Does this DC form a loop (completed closed circuit) or do you somehow have an isolated single straight wire in deep space and a current source on one side and a current sink on the other?
There is a reason Jesus wept.This is a takeoff from another thread where some people declare voltage to come first followed by current.
Hello,
As you should know, each application has it's own preferred method or at least each model has it's own requirements. Also, some people are bent on declaring one way of doing it over another but is there really an overall blanket preference? I dont think so.
But i must quote one line from your post in particular:
"That is because we cannot "inject" a current - a current is always the RESULT of an applied voltage"
That's not really true except again in a theory that prefers that definition. We can also say that voltage is the result of a current that flows from one place to another.
I believe the correct way to look at this is that they both occur simultaneously. A way of looking at this is that in order to establish a voltage you must move charge, and charge implies both current and voltage. simultaneously. In other words, energy.
Now it is true that some calculations will prefer one view over the other, but i think it is easy to see how both ideas can play out in real life.
If we "apply" a voltage to an inductor, current flows, but it does not 'start' to flow after the voltage is applied, it starts immediately. But even if we look at it as 'after' then what about the capacitor.
If we "apply" a voltage to a capacitor, we get infinite current flow even with a tiny capacitance. Now we could say that you have to apply a current 'first' in order to charge the capacitor to some voltage, so that the voltage comes 'after' the current. But that' also not right, they both occur simultaneously.
Now we might go as far as to say that the "electric field" is 'first' established in a wire before current can flow. But in that view we are talking about *relative* values of current and electric field. In this case we deem a current as low as 1 femtoampere (for example) to be zero current when really it is not zero. Again it has to be simultaneous. Also we can look at how that electric field got established in the first place.
So the bottom line is that current and voltage are independent only in theory and we decide what theory we want to use.
It's ok to disagree with this but then you should have at least one physical example that demonstrates the contrary.
Ha ha.There is a reason Jesus wept.
it’s all about potential energy of course, roll a fat man down a hill!You guys are real piece of work! In the best possible way.
All this talk about Mass,energy.
I bet none of you are brave enough to answer!
If mass and energy are the same thing,
how come the fatter you get, the lazier you become?
Well a little fun here and there but i guess we should get back on point.Obviously this thread has gone down hill!