Re: [Phys-l] accelerating charge

[Brian Whatcott <betwys1@sbcglobal.net>]

At 02:16 PM 2/12/2006, Antti, you wrote:
> Hi,
>
> there was some discussion about a year ago (Jan. 2005) on
> accelerating charge (uniform rectilinear acceleration) and if it
>  radiates or not. If it does and if the equivalence principle is true
> then also free-falling charges in a constant gravitational field should
> radiate according to the observers at rest. The February issue of
> AJP contains an article - "The radiation of a uniformly accelerated
> charge is beyond the horizon: A simple derivation" - which seems
> to answer the question.
>
> The authors state and provide an analysis that inertial observers do
>  detect radiation but co-moving observers (with respect to whom the
>  free-falling charges are at rest) do not! Their explanation is that
>  "the radiation field is confined to a spacetime region beyond a
> horizon that they cannot access". Moreover, they state that the
> concept of radiation has no absolute meaning and it depends
>  both on the radiation field as well as the state of motion
> of the observer.
>
> Does this seem right?
>
> Regards,
>
> Antti


I register a conflict between the assertion that
"radiation...depends both on the radiation field as well as the
state of motion of the observer."
and the usual statement that radiation transmission speed
 does not depend on the state of motion of the observer.

One might resolve the dissonance by asserting that the frequency
associated with radiation depends on both the radiation field as
 well as the state of motion of the observer.



Brian Whatcott    Altus OK    Eureka!