The fact that force fields contain an energy density leads to remarkable consequences for the radiation of accelerated force field sources.
The first consequence is that the fields are material subjects that always move with their source in the inertial frame of the source. The idea that field sources would permanently renew their immaterial force fields is refuted if these fields contain an energy density. A permanent renewal would then exhaust the source.
But the second consequence is more spectacular. The fact is that when a field is accelerated, it has to adapt its force field to the changed speed. We know that accelerated force field sources radiate. However, we have not yet noticed that the aperiodic part of this radiation is there to adapt the force field to the changed speed.
This adaptation is now the actual cause of the radiation from accelerated force field sources. So far, we have only focused on the periodic part of the radiation that is produced by accelerated charges or masses. But an aperiodic part is also part of such a situation.
Mathematically, the situation of an accelerated field source is described by an initial/boundary value problem. The solution to such a problem involves periodic and aperiodic parts.
This is a remarkable, very fundamental aspect that affects gravitational, electric and magnetic fields equally. In any case, this is worth a specific discussion.
No. The situation is much simpler: Objects in uniform motion are all equivalent and are described by a flat spacetime metric; objects in non-uniform motion are not equivalent and are described by a curved spacetime metric. Nothing else is needed.
Stam Nicolis "objects in non-uniform motion are not equivalent and are described by a curved spacetime metric"
What does your spacetime metric tell us about radiation?
What happens when accelerating? Why does the force field move with its source again after the acceleration has ended?
In your terms, objects can switch from flat to curved space-time and back. But that doesn't tell us anything about what's going on in curved space-time.
Wolfgang Konle ,
It is not clear that there is EM wave emission, due radiation reaction, for uniform acceleration. According to SR there should not be any radiation for uniform accelerated charges...
Stefano Quattrini
I don't think SR deals with any kind of acceleration, uniform or not, but is only applicable for things moving with uniform velocity, i.e. no acceleration.
I think accelerating charges do radiate. This would need to be described using GR, not SR, which is where the curved space-time metric comes in.
Stefano Quattrini "According to SR there should not be any radiation for uniform accelerated charges..."
Malcolm White is right. I am sure you know the Larmor radiation, which describes the periodic part of the radiation emitted by an accelerated charge. "Bremsstrahlung" is also related to this phenomenon.
But that such an acceleration also leads to an aperiodic emission, is the aspect which has not been considered yet.
The adaptation of force fields to a modified velocity of the field source leads to a fundamental conclusion. It proves that a negatively definite energy density of force fields cannot exist. The proof is simply based on the effect, that an accelerated field source only can emit positive power. With that emission the field source cannot adapt a field with a negative energy density to a modified velocity.
The conclusion is that the negative energy density of gravitational fields must be compensated by an omnipresent positive energy density.
The positive energy density must be strong enough to even compensate the gravitational field at the surface of neutron stars.
The presence of such a strong field sheds a new light on the models for elementary particles. The resulting new possibility is that as an example an electron could have a tiny kernel region in which the omnipresent strong field has been completely squeezed out by the gravitational field of the mass density equivalent of an electric field.
The giant pressure exerted by the strong gravitational field on the tiny field free region keeps the particle stable.
Within the tiny field free region, no gravity exists, because gravity is a reduction of the omnipresent cosmic field.
Wolfgang Konle
I was just pointing out what is the current orthodox view on this which is based also on the equivalence principle.
The a-periodic radiation is non-trivial, hard to find a radiation without a defined frequency.
Non-steady acceleration gives for sure EM radiation.
Constant acceleration may end up with additional stored energy in the field which is not radiated away in form of EM-waves. I guess during the transitories fro
Stefano Quattrini "why not the surface of black holes?"
Good question. But we simply don't know anything concrete about a surface of black holes.
On the surface of neutron stars, however, the energy density leads to an extremely high value, which is even in the range of the energy density of mc² in an atomic nucleus.
Such a high energy density adds a new actor to the model of elementary particles. A tiny zone in which this energy density is completely squeezed out could be present at the center of a stable elementary particle.
It is possible that a neutrino and an electric field is trapped in this zone. The external field, which compensates for the negative energy density, then prevents the particle from exploding.
I do not claim to know anything about the forces that hold the elementary particles together. The only claim is that we have to consider such an extremely strong dark energy field that compensates for the negative energy density of the gravitational field around neutron stars.
We have to take this field into account in cosmology and particle physics.
Stefano Quattrini "The a-periodic radiation is non-trivial, hard to find a radiation without a defined frequency."
We must not look for radiation! Instead, we need to look for a solution to the initial/boundary value problem imposed by the accelerated source of a force field that contains an energy density.
Such initial/boundary value problems always have an aperiodic term in their solutions. But without an energy density in the force field, the aperiodic term would be zero.
No, radiation from accelerated force field sources isn't simply the field adapting to a new velocity. It's a more complex phenomenon. Here's why:
- Charged particles are key: While we can discuss force fields, the underlying physics often involves charged particles. These particles, when accelerating, create distortions in the surrounding electric and magnetic fields.
- Disturbance travels outward: This distortion propagates outward from the source at the speed of light, carrying energy away. This propagating disturbance is what we observe as electromagnetic radiation.
- Not just a static shift: The radiation isn't just the field "catching up" to the moving particle. It's a new phenomenon altogether, distinct from the original static field.
Think of it like ripples on a pond. Throwing a stone creates a disturbance (acceleration) that travels outward (radiation) as waves, even though the water itself (the original field) isn't moving very far.
Here are some resources for a deeper dive:
- Lecture on radiation from accelerated charges YouTube
- How accelerating charges radiate https://physics.stackexchange.com/questions/89093/do-accelerated-charges-radiate-or-not
Murtadha Shukur "No, radiation from accelerated force field sources isn't simply the field adapting to a new velocity. It's a more complex phenomenon."
I never claimed that adapting the static force field around an accelerated field source to the new velocity is simple. The exact claim is that this field adaptation is subject of an initial / boundary value problem.
The point then is that initial / boundary value problems always have an aperiodic part in their solution.
This aperiodic part is not considered in the standard physics approach to the problem of radiation exerted by accelerated charges or masses.
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