Magnetic field does no work -- true in all branches of physics?

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Discussion Overview

The discussion centers around the concept of whether magnetic fields do work on charged particles across various branches of physics, including high energy physics. Participants explore the implications of this concept in different contexts, such as particle accelerators and synchrotron radiation.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant asserts that the magnetic field does no work on a charged particle because the force is always perpendicular to the velocity, which is a common explanation in introductory physics.
  • Another participant mentions synchrotron radiation as a potentially relevant topic, although they do not provide a detailed explanation.
  • A participant with experience in particle beam accelerators states that only electric fields can change the kinetic energy of charged particles, reinforcing the idea that magnetic fields do no work, even at relativistic speeds.
  • Another participant introduces the notion that a current loop or magnetic moment in a magnetic field can experience torque, which may lead to an increase in kinetic energy, suggesting a complexity to the original claim.

Areas of Agreement / Disagreement

Participants express differing views on the role of magnetic fields in doing work, with some supporting the idea that magnetic fields do no work universally, while others introduce scenarios that challenge this notion. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

There are limitations in the discussion regarding the definitions of work and energy in different contexts, as well as the specific conditions under which magnetic fields interact with charged particles.

CPW
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The force on a charged particle that is moving through a magnetic field is explained in introductory physics textbooks. The magnetic field cannot change the kinetic energy of the charged particle because the force from the magnetic field is always perpendicular to the velocity, so no work is done.

My question: Is that fact true in all branches of physics, such as high energy physics?
 
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Synchrotron radiation might be of your interest though I am not qualified to explain it.
 
anuttarasammyak said:
Synchrotron radiation might be of your interest though I am not qualified to explain it.

Hi. Thank you for the recommendation.

I studied particle beam accelerators, and those textbooks also state only the electric fields can be used to change the kinetic energy of the charged particle being accelerated. The magnetic fields do no work, even in situations when the charged particle's speed is relativistic. (The magnetic fields are used to steer the particle beam).

So, my thought is that magnetic fields do no work in all branches of physics. Even esoteric realms of which I am ignorant.

Please correct me if I am wrong about that.
 
It might interest the OP that a current loop and/or a magnetic moment in a magnetic field experiences a torque which can result in an increase in kinetic energy.
 
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