Can We Create a Magnetic Field Strong Enough to Stop High Energy Particles?

In summary, the conversation discusses the possibility of creating a strong enough magnetic field to stop high energy particles, similar to the Earth's magnetic field. It is mentioned that while a magnetic field cannot bring particles to a complete stop, it can be used to confine them in certain structures. The topic of Betatron accelerators and their potential to decelerate particles is also brought up. There is a discussion about constant versus varying magnetic fields and their effects on particle motion.
  • #1
nickdk
16
0
Is it possible to create a strong enough (artificial) magnetic field to stop high energy particles? Much like the Earth's magnetic field stops high energy particles.
 
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  • #2
Yes, in TOKAMAKs and Stellarators they create strong magnetic fields to confine high energy charged particles.
 
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  • #3
"Confining" and "stopping" are not the same thing.

If by "stopping", nickdk means "bringing to rest" or "making stationary", it's impossible for a magnetic field (by itself) to do that, because the magnetic force on a (charged) particle is always perpendicular to the particle's motion. It cannot change the particle's speed, only its direction of motion.
 
  • #4
jtbell said:
"Confining" and "stopping" are not the same thing.

If by "stopping", nickdk means "bringing to rest" or "making stationary", it's impossible for a magnetic field (by itself) to do that, because the magnetic force on a (charged) particle is always perpendicular to the particle's motion. It cannot change the particle's speed, only its direction of motion.

You are right, the total velocity cannot be put to zero by a magnetic field but there are magnetic "bottles" where a non-uniform magnetic field prevents particles from escaping (it "reflects" particles axially in the throat area). In certain sense it "stops" particles at some moment of reflection (I mean the axial part of motion).
 
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  • #5
Think of the betatron accelerator using the Faraday induction law to accelerate electrons to relativistic energies. The highest energy betatron ever built was over 300 MeV. Could the betatron dB/dt be reversed to decelerate 300 MeV electrons?
See
http://en.wikipedia.org/wiki/Betatron
The only requirement for the betatron magnetic field is that the guide field on the vacuum chamber be half the average field inside the area of the orbit (easy physics 201 problem). If B(t) stops increasing (it is a sine wave) and starts decreasing while maintaining this ratio with accelerated electrons in the vacuum chamber, the electrons will decelerate.
Bob S
 
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  • #6
We speak of a constant magnetic field, not of varying one. dB/dt = rotE, so it is E that actually makes this work.
 
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  • #7
Bob_for_short said:
We speak of a constant magnetic field, not of varying one. dB/dt = rotE, so it is E that actually makes this work.
The OP asked Is it possible to create a strong enough (artificial) magnetic field to stop high energy particles?, not strong enough constant magnetic field.
Bob S
 
  • #8
You are right.
 
  • #9
Interesting stuff. Thank you all :)
 

1. How is a magnetic field created?

A magnetic field is created by moving electric charges, such as electrons, which generate a magnetic force. This can be achieved through various methods such as using a magnetic material like iron, passing an electric current through a wire, or through electromagnetic induction.

2. What factors affect the strength of a magnetic field?

The strength of a magnetic field is affected by the distance from the source of the field, the amount of electric current flowing through the source, and the permeability of the material used to create the field. The direction of the field is also determined by the direction of the electric current.

3. How can a magnetic field be controlled or manipulated?

A magnetic field can be controlled or manipulated by changing the direction or strength of the electric current, using different materials with varying permeability, and by altering the distance between the source and the object affected by the field.

4. What are some practical applications of magnetic fields?

Magnetic fields have many practical applications, such as in electric motors and generators, MRI machines, speakers and headphones, and magnetic levitation trains. They are also used in particle accelerators, compasses, and various types of sensors.

5. How can magnetic fields be harmful to humans?

Exposure to strong magnetic fields can have negative effects on the human body, such as disrupting the function of pacemakers and other electronic devices, causing dizziness and nausea, and potentially damaging cells and tissues. However, the strength and duration of exposure play a significant role in determining the level of harm.

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