Plasmas created by a Nd:yttrium aluminum garnet laser show systematic changes in local electron temperature when bathed by a continuous wave laser of increasing irradiance. By monitoring the local electron density, the laser light absorption coefficient, and the signal to noise ratio in neutral emissions, we explain the changes in electron temperature and signal to noise to be a consequence of inverse bremsstrahlung in this new system of laser enhanced laser-induced plasmas.

When the krypton plasma in a DC glow discharge tube is exposed to an axial magnetic field, the turbulent energy and the characteristic dominant mode in the turbulent fluctuations are systematically and unexpectedly reduced with increasing magnetic field strength. When the index measuring the rate of transfer of energy through fluctuation scales is monitored, a lambda-like dependence on turbulent energy is routinely observed in all magnetic fields. From this, a critical turbulent energy is identified, which also decreases with increasing magnetic field strength.

A neodymium-doped yttrium aluminum garnet laser of wavelength 0.532 µm with the maximum energy of 900 mJ creates plasmas at a focal point in air in the path of a 1 kW continuous wave fiber laser of wavelength 1.08 µm. We find that there is an unexpected influence on a standard set of turbulent parameters in these laser-induced plasmas. Specifically, the continuous wave laser increased the complexity in the turbulent fluctuations. The continuous wave laser reduces the characteristic fluctuation frequencies in the neutral lines. Furthermore, the continuous wave laser enhances turbulence energies in ions while it diminishes turbulence energies in neutrals.

A direct current glow discharge tube is used to determine how mass changes the effects of certain turbulence characteristics in a weakly ionized gas. Helium, neon, argon, and krypton plasmas were created, and an axial magnetic field, varied from 0.0 to 550.0 Gauss, was used to enhance mass dependent properties of turbulence. From the power spectra of light emission variations associated with velocity fluctuations, determination of mass dependency on turbulent characteristic unstable modes, energy associated with turbulence, and the rate at which energy is transferred from scale to scale are measured. The magnetic field strength is found to be too weak to overcome particle diffusion to the walls to affect the turbulence in all four types of plasmas, though mass dependency is still detected. Though the total energy and the rate at which the energy moves between scales are mass invariant, the amplitude of the instability modes that characterize each plasma are dependent on mass. V C 2013 AIP Publishing LLC. [http://dx.