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Kemal
2005-Mar-26, 12:52 AM
Would a particle beam be visible in space? I know lasers aren't, I was just curious.

Bathcat
2005-Mar-26, 08:59 PM
In order for it to be visible it would have to radiate light. If a particle beam smacked into a cloud of interstellar gas, it could produce light. Charged particles can cause Cherenkov radiation, but not (if I understand it correctly) in a vacuum. See this link. (http://rd11.web.cern.ch/RD11/rkb/PH14pp/node26.html)

If a charged particle is accelerated it will emit radiation, but if you fire a beam of charged particles from an accelerator into space then the acceleration only occurs inside the device.

The upshot, I think, is that the particle beam has to interact with something in order to produce visible light. It won't glow on its own in a vacuum.

But I could very well be dead wrong! I am just speculating, off the top of my head.

ngc3314
2005-Mar-26, 09:22 PM
In order for it to be visible it would have to radiate light. If a particle beam smacked into a cloud of interstellar gas, it could produce light. Charged particles can cause Cherenkov radiation, but not (if I understand it correctly) in a vacuum. See this link. (http://rd11.web.cern.ch/RD11/rkb/PH14pp/node26.html)

If a charged particle is accelerated it will emit radiation, but if you fire a beam of charged particles from an accelerator into space then the acceleration only occurs inside the device.

The upshot, I think, is that the particle beam has to interact with something in order to produce visible light. It won't glow on its own in a vacuum.

But I could very well be dead wrong! I am just speculating, off the top of my head.

If it goes through a region threaded by a magnetic field, the charged particles will be accelerated and radiate (for relativistic particles it's the case of synchrotron radiation). Which way the radiation is directed depends on the particles' internal velocity spread, and the intensity and tightness of its forward beaming also fold in the field strength and particle energy. This annoys high-energy physicists no end by sapping the very energy they work so hard to pack into the beams, but it's the bread-and-butter of radio astronomers.

Bozola
2005-Mar-27, 02:12 AM
Would a particle beam be visible in space? I know lasers aren't, I was just curious.

http://www.ftlcomm.com:16080/ensign/industry/hightechwood/Ibeams.jpg

I would think that these particle beams would reflect no differently than they do on Earth.

Kebsis
2005-Mar-27, 02:32 AM
I think that if I had a space fighter, and I wanted weapons that had a cool tracer effect in space, I would just use bullets with tracers of some kind.

Bathcat
2005-Mar-27, 02:41 AM
ngc3314 -- Yeah, of course. I didn't think of synchrotron radiation. You're right.

Mel Brooks might be interested in a space battle using Bozola's particle beams, don't you think?

That's actually a cool name.

"Fire the Bozola Particle Beam Cannon, lieutenant Sprockette!"

"Sir! A signal from the Nastigie flagship! It says...'How much wood would a spaceship chuck if a spaceship could chuck wood?'"

"Those....fiends!"

Kaptain K
2005-Mar-27, 06:26 AM
Dang! Now I have to clean the Pepsi out of my keyboard! =D>

tlbs101
2005-Mar-28, 09:54 PM
A neutral particle beam experiment was flown into space in the late 1980's. Called BEAR, the accelerator was developed at Los Alamos and flown sub-orbital from White Sands missile range.

A camera on-board the small spacecraft recorded the firing of the beam in space. I got to see the video tape recording.

The beam reacted with the few oxygen and nitrogen molecules that were present 70 miles up and made a very cool looking green "beam".

Because the particle beam was actually an ion beam of Hydrogen that was pumped through Xenon gas to pick up an electron to make it neutral, and because that process was not 100% efficient, there were actually 2 beams -- the straight neutral beam and one that curved.

I would imagine in "deep" space where there are even fewer molecules of any kind of gas, that a particle beam would be invisible.