How Does a Charge Exert Force on Itself?

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SUMMARY

The discussion centers on the self-force exerted by a charge in an electromagnetic field, specifically addressing how a charge contributes to its own electric field while also being influenced by it. The work done on a charge q is expressed as F.dl=q(E+v×B), leading to the conclusion that the charge's movement is influenced by both electric and magnetic fields generated by a current configuration. The participants emphasize the importance of considering the entire field during calculations, as outlined in Griffiths' textbook on electromagnetism.

PREREQUISITES
  • Understanding of electromagnetic fields, specifically electric field E and magnetic field B.
  • Familiarity with the Lorentz force equation and its components.
  • Knowledge of charge distribution and its impact on field calculations.
  • Proficiency in calculus, particularly integration, for analyzing field contributions.
NEXT STEPS
  • Study Griffiths' "Introduction to Electrodynamics" for a deeper understanding of self-force in electromagnetic fields.
  • Explore the implications of charge distribution on electric fields using integration techniques.
  • Research the Lorentz force law and its applications in various charge configurations.
  • Examine case studies involving moving charges in magnetic fields to solidify understanding of the concepts discussed.
USEFUL FOR

This discussion is beneficial for physics students, particularly those studying electromagnetism, as well as researchers and educators looking to deepen their understanding of self-forces in electric and magnetic fields.

Avi Nandi
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Suppose some charge and current config is present which at time t produces fields
E and B. In the next instant dt the charges
move around a bit.
Work done on the charge q
F.dl=q(E+v×B).vdt=qE.vdt
dW/dt= qE.v

Now the question is q has also contribution in the field E. How the charge is exerting force on itself?
 
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Unless your charge has some actual and variable distribution in space (then you probably need integration), ignore the field of a given charge to calculate how that charge moves.
 
The problem: there is a charge and current configuration. Electric field and magnetic field originates from this configuration. The charges now move under the influence of the field in time dt. What is the work done by the field?
While calculating the work done we take force as ∫ρ(E+v×B).vdt dV. Why the same field originating from ρ exerting force on it?

We are not ignoring the field of the charge on which we are calculating force, the problem is the whole field is taken during calculation.
I am following the book written by Griffiths.
 

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