Can a Charged Particle Spin Indefinitely in a Magnetic Field?

[username]

If a charged particle experiences a force in a magnetic field would it be possible to introduce a charged particle into an magnetic field and keep it spinning around in circles indefinately whether its in a vacuum or not.

 

[jimmy p]

I should assume so, as long as the particle was moving fast enough. Sometimes when we are bored in physics, the teacher gets his big magnet out and we see how far round a paper clip will go if we throw it through the gap in the magnet. Obviously we have never had an orbiting paperclip but i believe that if the density of the flux was high and the particle moving fast enough, then it could happen.

Well, it works for gravity don't it?

 

[username]

Now all I need is a paperclip :). What if you put two charged plates perpendicular to the direction of the magnetic field. Would the particle gain more kinetic energy if it is traveling round in circles (more time spent between the plates) than if it went in a strait line between the plates?

 

[jimmy p]

as long as the plates were the opposite charge to the particle. I am not sure what you mean about perpendicular to the field, a magnetic field is usually all around an object.

 

[jcsd]

Yes, that's what a cyclotron is:

http://scienceworld.wolfram.com/physics/Cyclotron.html

If it's not in a vacuum sooner or later it's going collide with another particle.