Small question about constantly accelerating charges

[gneual]

I've seen the question of whether a constantly accelerating charged particle emits EM radiation posed in the context of gravitational acceleration and apparently is an open question, and answers bringing up the "equivalence principle", such as in the following threads:

https://physics.stackexchange.com/q...accelerating-in-a-gravitational-field-radiate
https://physics.stackexchange.com/q...ing-charged-particle-emit-em-radiation-or-not
https://physics.stackexchange.com/questions/89093/do-accelerated-charges-radiate-or-not

But for other sources of uniform acceleration on a charged particle, it is not controversial right? Such as when the Lorentz electric force causes a particle in a uniform electric field to undergo uniform linear acceleration; this indeed emits electromagnetic radiation on a continuous spectrum according to Larmor's formula and is not a controversy right?

 

[Dale]

The question is not particularly controversial if the person asking the question clarifies one specific point that is usually neglected:

How do you intend to measure the radiation? Specifically, are you measuring it with an inertial antenna or a co-accelerating antenna?

 

[gneual]

I see, so whether it is controversial depends on how it is interpreted, specifically the inertial reference frame? So the cause of the acceleration -- such as electric part of the Lorentz force, or gravity, is irrelevant here?

 

[Dale]

I see, so whether it is controversial depends on how it is interpreted, specifically the inertial reference frame?

Not the reference frame. The proper acceleration of the antenna is what matters. Is the antenna inertial or co-accelerating.

So the cause of the acceleration -- such as electric part of the Lorentz force, or gravity, is irrelevant here?

Yes

 

[Meir Achuz]

The question is not particularly controversial if the person asking the question clarifies one specific point that is usually neglected:

How do you intend to measure the radiation? Specifically, are you measuring it with an inertial antenna or a co-accelerating antenna?

The papers I have seen do not mention whether the antenna is accelerating or not.
My feeling is that AE never mentioned EM when he stated the equivalence principle, and died drying to combine Relativity and EM.

 

[Dale]

died drying to combine Relativity and EM

He did that in his 1905 paper “On the electrodynamics of moving bodies”. Well before his death.

 

[Meir Achuz]

He did that in his 1905 paper “On the electrodynamics of moving bodies”. Well before his death.

I meant applying his equivalence principle to EM radiation.

 

[Sagittarius A-Star]

I meant applying his equivalence principle to EM radiation.

According to Wolfgang Rindler, the EP cannot be applied to the "paradox" of an accerated charge, because it's field is not local. An electric charge at rest on the surface of the earth does not radiate by energy conservation.
A charge, fixed inside an orbiting satellite, does radiate.

Source (Relativity: Special, General, and Cosmological, 2nd edition, chapter 1.15):
https://www.amazon.com/Relativity-S...fgang-Rindler/dp/0198567324?tag=pfamazon01-20

However, Wikipedia shows answers from other physicists, that disagree:
https://en.wikipedia.org/wiki/Paradox_of_radiation_of_charged_particles_in_a_gravitational_field

 

[MervG]

I think this is related to your question. Are you familiar with "radiation reaction force"? AKA Abraham-Lorentz force? https://en.wikipedia.org/wiki/Abraham–Lorentz_force

Based on that equation, the reaction force is generated from a change of acceleration (Jerk), rather than acceleration itself...
But at the same time, wouldn't a steadily accelerating charge also generate an electromagnetic wave? That is what the mentioned Larmor formula indicates. So wouldn't even a steady acceleration cause some sort of reaction force from the particle?

 

[Dale]

wouldn't a steadily accelerating charge also generate an electromagnetic wave?

This requires the same clarification I mentioned above. How are you detecting the possible electromagnetic wave? IE are you using an antenna that is free falling past the charge or one that is co-accelerating with the charge?

 

[Sagittarius A-Star]

I think this is related to your question. Are you familiar with "radiation reaction force"? AKA Abraham-Lorentz force? https://en.wikipedia.org/wiki/Abraham–Lorentz_force

View attachment 370580

Based on that equation, the reaction force is generated from a change of acceleration (Jerk), rather than acceleration itself...

According to Wikipedia, this is a non-relativistic equation. The relativistic equation is shown below in Wikipedia.
https://en.wikipedia.org/wiki/Abraham–Lorentz_force#Definition_and_description

The same question regarding the relativistic equation is discussed in the Wikipedia article under "Hyperbolic Motion":
https://en.wikipedia.org/wiki/Abraham–Lorentz_force#Hyperbolic_motion