- #1

- 3

- 0

Thanks

Menachem

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

- Thread starter menachem
- Start date

- #1

- 3

- 0

Thanks

Menachem

- #2

- 62

- 0

I would need to know what is the state of the art about the study of the radiation emitted by an accelerated charge. According to classical EM theory,does a uniformly accelerated charge emit radiation? Or is the radiation proportional to the 3rd time derivative of position (so that a non-uniformly accelerated charge radiates..).When a charged body radiates (= loses energy) how can one observe the energy loss of the body? Is it still an open point in today's physics or has it been sorted out?

Thanks

Menachem

No I don't think so - Bremstrahhlung radiation (is that what you are referring to?) is given off when electrons deflect off charged particles - if there is deflection, the acceleration isn't uniform.

One can measure the energy loss by using a scintillation counter (I think that's what you call it).

- #3

- 4,662

- 7

Bob S

*See Panofsky and Phillips, "Classical Electricity and Magnetism", Addison Wesley, page 302, Eq 19.22

Last edited:

- #4

- 3

- 0

I don't know about x-ray tubes, but in antennas charges are not uniformly accelerating (they are subjected to a sinusoidal electric field).

Excuse my naivetè but i'll try to make an example: if I have an electrically charged iron ball (so a macrscopic charged body, which should act according to classical EM theory) and I drop it from the top of a tower, does it radiate?

(as soon as possible I'll try to have a look at the reference you Bob point me at)

Thanks

Menachem

- #5

- 62

- 0

I don't know about x-ray tubes, but in antennas charges are not uniformly accelerating (they are subjected to a sinusoidal electric field).

Excuse my naivetè but i'll try to make an example: if I have an electrically charged iron ball (so a macrscopic charged body, which should act according to classical EM theory) and I drop it from the top of a tower, does it radiate?

(as soon as possible I'll try to have a look at the reference you Bob point me at)

Thanks

Menachem

Yes it would, although the amount of energy would be miniscule. This link might be useful:

http://hyperphysics.phy-astr.gsu.edu/HBASE/Particles/synchrotron.html

- #6

- 4,662

- 7

Yes. According to Panofsky and Phillips "Classical Electricity and Magnetism" Eq 19.22, the radiated power for aif I have an electrically charged iron ball (so a macrscopic charged body, which should act according to classical EM theory) and I drop it from the top of a tower, does it radiate?

Yes it would, although the amount of energy would be miniscule. This link might be useful:

http://hyperphysics.phy-astr.gsu.edu/HBASE/Particles/synchrotron.html

This link is for

Bob S

Last edited:

- #7

- 3

- 0

The link provided by vertices is actually about a uniformly accelerating charge (what I was looking for), and the formula provided there agrees with the proportion given by Bob: -dW/dt = ~[du/dt]2 (the minus sign is negligible here, being due to a convention). The first formula given in this link is presented as valid for any accelerated charge. I would like to know if this is a "unifying formula" that works for (uniformly and not uniformly) accelerated charges, and not only and not only acceleration perpendicular to velocity. And secondly again I'd like to know what kind of energy loss happens in an accelerating charged macroscopic body that radiates? Is it energy loss of electrons going from a higher-energy to a lower-energy level?

Thanks

Menachem

- #8

- 621

- 4

Share:

- Replies
- 14

- Views
- 392

- Replies
- 4

- Views
- 694

- Replies
- 5

- Views
- 394

- Replies
- 3

- Views
- 434

- Replies
- 18

- Views
- 527

- Replies
- 2

- Views
- 459

- Replies
- 10

- Views
- 573

- Replies
- 14

- Views
- 291

- Replies
- 42

- Views
- 2K

- Replies
- 2

- Views
- 504