# Charged particle beam

1. Apr 10, 2005

### sid_galt

What physics is required to analyze the motion and dynamics of a charged particle beam?
Is just the analysis of electrical fields by charged particles on each other sufficient or is there a lot more to it?

2. Apr 10, 2005

### Danger

Interaction with the atmosphere plays a role, if you are talking about a long beam outside of a vacuum environment. I don't know any of the math. Generally the first pulse will create an evacuated channel in the air for others to follow. I don't know how ionization of the air might interact with the field around the beam. The beam will repel itself out of focus after a short distance, so energy density drops like crazy. I didn't investigate the subject much more than that, since it was just for a novel is was writing.

3. Apr 11, 2005

### Meir Achuz

The equations governing the motion of charged particles are:
dW/dt=qv.E
dp/dt=q[E+vXB].

4. Apr 11, 2005

### ZapperZ

Staff Emeritus
Your question is rather vague. You need to specify under what conditions are you trying to "analyze" such motion.

In particle accelerators, there are numerical codes (such as PARMELA for linear electron accelerators) that practically track the evolution of the particles down the beam pipe under various conditions. This includes their interaction with each other in the form of the space-charge effects.

There are also varying level of complexities that can be included in different situations, such as that done in plasma dynamics in which self-energy interactions can become significant.

Thus, unless you have something specific in mind, this question is too vague to answer.

Zz.

5. Jul 24, 2010

### Malleolus

You also have to take into consideration that the particles will strip the electrons from the air as well, that the emf generated by the particle's flow would help to maintain the beam over a given distance as long as you can maintain a consistent pulse.

6. Jul 24, 2010

### AJ Bentley

That's a can of worms in itself, You want more?!

Seriously though: The equations may be simple - the application is most definitely not. It's the old three body problem - with a whole lot more than three bodies.

7. Jul 24, 2010

### K^2

Well, if you have a lot of objects, you can throw it all into a stat-mech approach. Find average attraction/repulsion potentials, and throw them into free energy, then treat everything as a gas. Eventually, developing hydrodynamics equations for it.

But yeah, that requires a lot more than understanding of basic interactions between particles.

8. Jul 24, 2010

### ZapperZ

Staff Emeritus
I hope you realize that you're responding to a thread that has its last activity in 2005.

Zz.

9. Jul 24, 2010

### AJ Bentley

Don't you EVER take out the garbage?