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I Particle in an Electromagnetic Field

  1. Jan 27, 2017 #1
    Using the Lagrangian : L = ½mv^2 - qφ + qAv

    What is the physical intuition of Av ? I know that A is the magnetic vector potential and that v is the velocity of the charged particle. I just don't know what their dot product means physically .
  2. jcsd
  3. Jan 28, 2017 #2


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    I find your expression hard to read/interpret. Fortunately, it's all chewed out thoroughly here . With the 'explanation':
    In other words: if you start with the Lorentz force law and do the math backwards (ahem) you (can) end up with this form for the Lagrangian.

    "It works" is a also a good argument for a physicist ( I try to avoid the word intuition )
  4. Jan 28, 2017 #3
    Well, 1/2mv^2 is kinetic energy of the particle , qφ is the coulomb potential of electricity . So we know what the other components of the equations are. So my question really is what does the term qvA mean ? It's something to do with magnetism, but what exactly ?
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