Particle in an Electromagnetic Field

In summary, the Lagrangian L = ½mv^2 - qφ + qAv is a form of the Lorentz Force Law that allows us to solve for the force vector F. This expression relates to the kinetic energy and coulomb potential of the particle, and the term qvA represents the magnetic vector potential and the velocity of the charged particle. This term is a key component in understanding the physical intuition behind the Lorentz Force Law and its application in solving for the force vector.
  • #1
SpaceNerdz
20
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 .
 
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  • #2
Hi,

I find your expression hard to read/interpret. Fortunately, it's all chewed out thoroughly here . With the 'explanation':
we can solve .. for ##\vec F##: ... which is just the correct expression for the Lorentz Force Law

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 )
 
  • #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 ?
 

FAQ: Particle in an Electromagnetic Field

1. What is a particle in an electromagnetic field?

A particle in an electromagnetic field refers to a charged particle, such as an electron or a proton, that is affected by an electric and magnetic field. These fields can be created by other charged particles or by electromagnetic radiation.

2. What is the equation for the motion of a particle in an electromagnetic field?

The equation for the motion of a particle in an electromagnetic field is known as the Lorentz force law, which states that the force on a charged particle is equal to the product of its charge, its velocity, and the cross product of the electric and magnetic fields it is experiencing.

3. How does the presence of an electromagnetic field affect the trajectory of a particle?

The presence of an electromagnetic field can cause a charged particle to experience a force, which can alter its trajectory. The direction and magnitude of the force depend on the strength and orientation of the electric and magnetic fields, as well as the charge and velocity of the particle.

4. Can a particle in an electromagnetic field change its energy?

Yes, a particle in an electromagnetic field can change its energy due to the work done by the electric and magnetic fields. If the particle moves in the direction of the electric field, it gains kinetic energy, while if it moves perpendicular to the magnetic field, it can gain or lose energy depending on its charge and direction of motion.

5. What are some real-world applications of studying particles in electromagnetic fields?

Studying particles in electromagnetic fields has many practical applications, such as in particle accelerators used in medical treatments and scientific research, in electronics and telecommunications technology, and in understanding the behavior of charged particles in space, such as the auroras and solar flares.

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