Radiation reaction

Below an electron initially at rest in a rotating em-field lying in the xy-plane is considered with a0=10000. The em-field has a Gaussian intensity distribution and is centered at the origin of the coordinate fame. As the electrons starts to move radiation friction confines it to the high intensity region of the external field. Equations of motion for the quiding center of the accelerating electron can be derived. Their solution is plotted as a red solid line in the plot below. Due to the guiding center dynamics the confinement time of the radiating electron is much prolonged. The black solid line shows the trajectory of the electron without radiation friction. In that case the electron leaves the high field region immediately.

The plot below shows the distance from the center of a single radiating electron in the strong rotating em-field with a0=800. It resides for a prolonged time in the high field region of the driver field:

The plot below shows a PSC simulation of the radial distribution of an ensemble of radiating electrons in a super-strong rotating em-field with a0=800. The density of the electron ensemble is n0=10²⁰/ccm. The inset in the plot below shows that the center of mass of the electron ensemble obeys a guiding center motion as is expected. The yellow line to the left of the plot shows the radius if the center of mass of the ensemble from the origin of the rotating electromagnetic field under the assumption of no radiation reaction. It is seen that radiating electrons remain in the high field domain for considerably extended time. It can also be seen that there is a critical radius for confinement:

The plot below shows trapping obtained with the quantum emission model. Trapping times are shorter due to the quantum fluktuations of the emission process:

The plot below shows a PSC simulation of the radial distribution of an ensemble of radiating electrons for three different radiation models. The blue line follows the Newton-Lorentz force equation. There is no radiation friction. The green curve shows results with radiation friction but without quantum fluctuations during the emssion process. The red curce in the plot shows results with radiation friction and quantum fluctuations during the emission process:

The movie below shows the configuration space confinement of electrons due to strong radiation emission. The plot gives the density of the radiating electron distribution wiggling around the em-field center. The details of the radial distribution are given above: