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

Click For Summary

Discussion Overview

The discussion centers on the feasibility of creating an artificial magnetic field strong enough to stop high energy particles, drawing parallels to the Earth's magnetic field. It explores theoretical and practical aspects, including confinement techniques and the behavior of charged particles in magnetic fields.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants propose that strong magnetic fields, such as those in TOKAMAKs and Stellarators, can confine high energy charged particles.
  • Others argue that "stopping" and "confining" are not synonymous, emphasizing that a magnetic field cannot bring a charged particle to rest, as it only alters the direction of motion.
  • A participant mentions the concept of magnetic "bottles" that can reflect particles, suggesting that they can "stop" particles at certain moments of reflection.
  • One participant introduces the betatron accelerator and questions whether reversing the magnetic field could decelerate high energy electrons, referencing specific physics principles related to magnetic fields.
  • Another participant clarifies that the discussion should focus on constant magnetic fields rather than varying ones, highlighting the role of electric fields in the process.

Areas of Agreement / Disagreement

Participants express differing views on the definitions of "stopping" versus "confining" particles, and there is no consensus on whether a magnetic field can effectively stop high energy particles. The discussion remains unresolved regarding the implications of varying versus constant magnetic fields.

Contextual Notes

Limitations include the dependence on definitions of "stopping" and "confining," as well as the unresolved nature of the mathematical principles involved in the proposed scenarios.

nickdk
Messages
16
Reaction score
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.
 
Physics news on Phys.org
Yes, in TOKAMAKs and Stellarators they create strong magnetic fields to confine high energy charged particles.
 
Last edited:
"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.
 
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).
 
Last edited:
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
 
Last edited:
We speak of a constant magnetic field, not of varying one. dB/dt = rotE, so it is E that actually makes this work.
 
Last edited:
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
 
You are right.
 
Interesting stuff. Thank you all :)
 

Similar threads

High School How Much Energy is Stored in Earth's Magnetic Field?
  • · Replies 2 ·
Replies
2
Views
3K
Undergrad Charge movement relative to magnetic field frame dependence/invariance
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad Can nested solenoids trap particles?
  • · Replies 12 ·
Replies
12
Views
2K
Undergrad How can magnetic fields contain energy?
  • · Replies 17 ·
Replies
17
Views
3K
High School Magnetic Field & Particle Spin: Does It Matter?
  • · Replies 5 ·
Replies
5
Views
2K
High School Experiment issues (electromagnetism)
  • · Replies 42 ·
2
Replies
42
Views
4K
Undergrad Magnetic Resonance physics question: RF pulse role and 'in-phase'
  • · Replies 16 ·
Replies
16
Views
4K
High School A Magnetic Misconception on Divergence 0/Closed Field Lines?
  • · Replies 3 ·
Replies
3
Views
1K
Undergrad Induced Electric and Magnetic Fields Creating Each Other
  • · Replies 3 ·
Replies
3
Views
2K
High School Seeing both B field lines and E field lines at the same time
  • · Replies 22 ·
Replies
22
Views
3K