Particle-in-Cell Modeling of Laser Thomson Scattering in Low-Density Plasmas at Elevated Laser Intensities
Incoherent Thomson scattering is a non-intrusive technique commonly used for measuring local plasma density. Within low-density, low-temperature plasma's and for sufficient laser intensity, the laser may perturb the local electron density via the ponderomotive force, causing the diagnostic to become intrusive and leading to erroneous results. A theoretical model for this effect is validated numerically via kinetic simulations of a quasi-neutral plasma using the Particle-in-Cell technique.
Ponderomotive perturbations of low density low-temperature plasma under laser Thomson scattering diagnostics
The ponderomotive perturbation in the interaction region of laser radiation with a low density and low-temperature plasma is considered. Estimates of the perturbation magnitude are determined from the plasma parameters, geometry, intensity, and wavelength of laser radiation. It is shown that ponderomotive perturbations can lead to large errors in the electron density when measured using Thomson scattering.
Plasma Production Using Energetic Meandering Electrons
When an electron is accelerated by an oscillating electric field in an inhomogeneous magnetic field which has a null point, it meanders along a chaotic orbit. The kinetic energy becomes larger than that of regular motion in an off-resonant homogeneous magnetic field. This effect explains the high efficiency of plasma production in the neutral line discharge (NLD).