Re: Self-forces

In article <200609190746.k8J7kQq7022076@xxxxxxxxxx>, Bruce Scott TOK <Use-Author-Supplied-Address-Header@[127.1]> writes:
Timo N wrote:

On Sat, 16 Sep 2006, Bruce Scott TOK wrote:

Try googling with: self forces electrodynamics

also: look up articles by Steve Parrott in sci.physics.research a few
years ago when there were lively (and well informed) threads on the topic

I'm not sure how much this will reveal about what is clear and what is not
clear. Perhaps a better rule of thumb would be that if it isn't in (and
clear in) Griffiths and Jackson, it isn't clear.

That's a good point. Basically, the point of Parrott's book is that
this stuff has never been solved.

For me the best elementary treatment of the problems with the problem is
the one in Feynman's Lectures, Vol II, where he asks precisely that
question: what it the force of an electron on itself.

At rest the self-produced electric field is symmetric and the force is
zero. In motion, considering relativity, that is no longer true and you
get infinities. Feynman makes an insightful connection between that and
the infinities in QED (in commentary... QED itself is of course beyond
the scope of the lectures).

In sci.physics about 10 years ago the thing that started the whole
discussion was when someone asked if a charge at rest in a gravitational
field should radiate (massless charged particle near a gravitating
object with relative velocity of zero to be precise).

I got the impression from the discussion (long, with Parrott involved)
that there is no rigorous answer to that question in any reasonable
theory.

That's my impression as well. And, yes, the classical divergences and
the QED ones are not unrelated.

Mati Meron | "When you argue with a fool,
meron@xxxxxxxxxxxxxxxxx | chances are he is doing just the same"
.

Relevant Pages

  • Re: Self-forces
    ... look up articles by Steve Parrott in sci.physics.research a few ... field should radiate (massless charged particle near a gravitating ... I got the impression from the discussion ... Why *would* one expect an electron to exert a force on itself? ...
    (sci.physics)
  • Re: Self-forces
    ... look up articles by Steve Parrott in sci.physics.research a few ... the infinities in QED (in commentary... ... field should radiate (massless charged particle near a gravitating ...
    (sci.physics)
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