Inverse Bremsstrahlung Absorption in an Unmagnetized Plasma With a Kappa Distribution Function

In thermonuclear fusion, one of the ways of laser energy absorption is called collisional absorption or inverse bremsstrahlung (IB) absorption. The present research is an attempt to calculate the IB absorption in homogeneous and unmagnetized plasma through the kinetic theory and the Fokker-Planck equation. The isotropic distribution function, f
₀
, is considered as the Kappa distribution, and the IB absorption is calculated according to the laser electric field and the electric current in plasma. As the results show, the IB absorption value increases at short laser wavelengths, low spectral indices, κ, and low electron temperatures. The theoretical study of IB absorption offered in this research allows optimizing the parameters of laser and plasma to obtain good energy efficiency in inertial confinement fusion experiments.