Ponderomotive energy

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In strong-field laser physics, ponderomotive energy is the cycle-averaged quiver energy of a free electron in an electromagnetic field.[1]

Equation[edit]

The ponderomotive energy is given by

,

where is the electron charge, is the linearly polarised electric field amplitude, is the laser carrier frequency and is the electron mass.

In terms of the laser intensity , using , it reads less simply:

,

where is the vacuum permittivity.

Atomic units[edit]

In atomic units, , , where . If one uses the atomic unit of electric field,[2] then the ponderomotive energy is just

Derivation[edit]

The formula for the ponderomotive energy can be easily derived. A free electron of charge interacts with an electric field . The force on the electron is

.

The acceleration of the electron is

.

Because the electron executes harmonic motion, the electron's position is

.

For a particle experiencing harmonic motion, the time-averaged energy is

.

In laser physics, this is called the ponderomotive energy .

See also[edit]

References and notes[edit]

  1. ^ Highly Excited Atoms. By J. P. Connerade. p. 339
  2. ^ CODATA Value: atomic unit of electric field