Subluminal Cherenkov radiation

In summary: This study looked at the theory behind Cherenkov radiation and found that it can occur at subluminal speeds, contrary to previous belief that it only occurs at superluminal speeds. They used charged particles to emit the radiation and confirmed this through experiments using subpicosecond laser pulses.
  • #1
Zefram
147
0
Does anyone have any more information on the following (I haven't looked yet)?

Subluminal Cherenkov radiation. In vacuum, nothing travels faster than light. In transparent substances like water, however, it is possible for high-energy charged particles to exceed the speed of a light beam in that substance. When this happens, the particle will radiate a cone of light called Cherenkov radiation. A team of researchers (University of Michigan and Max Planck Institute for Condensed Matter Research in Stuttgart) has now taken a closer look at the theory, and found that conical Cherenkov emission also occurs at subluminal speeds. The researchers verified the finding experimentally using subpicosecond laser pulses to generate--through a nonlinear optical process--relativistic dipoles that emitted infrared Cherenkov radiation in a zinc selenide crystal. (T. E. Stevens et al., Science 291, 627, 2001.) --pfs

http://www.physicstoday.org/pt/vol-54/iss-3/p9.html
 
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  • #2
You seem to have mentioned all there is to
know about it. One important thing is that
only charged particles can release it.

All I can tell you is that they use that cone
of light from Cherenkov Radiation to detect
nuetrinos, which are normally extremely hard
to detect because of their very low mass and
zero charge.

Look up how the Super Kamiokande detector works,
and that should explain quite a lot about how
they put this radiation to use.
 
  • #3
Am I misreading that or are they saying that charged particles don't even need to move faster than the speed of light in that medium to emit the radiation? What are relativistic dipoles?

The researchers verified the finding experimentally using subpicosecond laser pulses to generate--through a nonlinear optical process--relativistic dipoles that emitted infrared Cherenkov radiation in a zinc selenide crystal.
 

1. What is subluminal Cherenkov radiation?

Subluminal Cherenkov radiation is a type of electromagnetic radiation that is emitted when a charged particle travels through a medium at a speed slower than the speed of light in that medium. It is named after the Soviet physicist Pavel Cherenkov, who first observed this phenomenon in 1934.

2. How is subluminal Cherenkov radiation different from normal Cherenkov radiation?

Normal Cherenkov radiation occurs when a charged particle travels through a medium at a speed faster than the speed of light in that medium. This results in a cone of light being emitted at a specific angle. Subluminal Cherenkov radiation, on the other hand, occurs when the charged particle is traveling at a slower speed, resulting in a different angle and intensity of emitted light.

3. What causes subluminal Cherenkov radiation?

Subluminal Cherenkov radiation is caused by the interaction between a charged particle and the atoms or molecules in a medium. When the charged particle travels through the medium at a speed slower than the speed of light, it disrupts the electric field of the atoms or molecules, causing them to emit photons of light.

4. What are some applications of subluminal Cherenkov radiation?

One application of subluminal Cherenkov radiation is in particle detectors, where the emitted light can be used to track the path of charged particles. It is also used in medical imaging techniques, such as positron emission tomography (PET), to detect and visualize the movement of radioactive particles in the body.

5. Can subluminal Cherenkov radiation be faster than the speed of light in a vacuum?

No, subluminal Cherenkov radiation always travels slower than the speed of light in a vacuum. It is a result of the charged particle traveling through a medium, which slows down its speed compared to the speed of light in a vacuum.

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