Ponderomotive energy

In strong field laser physics, the term Ponderomotive Energy refers to the cycle averaged quiver energy of a free electron in an E-field as given by,

$U_{p}=e^{2}E_{a}^{2}/4m\omega _{0}^{2}$

Where $e$ is the electron charge, $E_{a}$ is the linearly polarised electric field amplitude, $\omega _{0}^{2}$ is the laser carrier frequency and $m$ is the electron mass.

In terms of the laser intensity $I$, using $I=c\epsilon _{0}E_{a}^{2}/2$, it reads less simply $U_{p}=e^{2}I/2c\epsilon _{0}m\omega _{0}^{2}=2e^{2}/c\epsilon _{0}m\times I/4\omega _{0}^{2}$. Now, atomic units provide $e=m=1$, $\epsilon _{0}=1/4\pi$, $\alpha c=1$ where $\alpha \approx 1/137$. Thus, $2e^{2}/c\epsilon _{0}m=8\pi /137$.

See also

• Ponderomotive force
• Harmonic generation