Enhanced damping of ion acoustic waves in dense plasmas

A theory for the ion acoustic wave damping in dense plasmas and warm dense matter, accounting for the Umklapp process, is presented. A higher decay rate compared to the prediction from the Landau damping theory is predicted for high-Z dense plasmas where the electron density ranges from $10^{21}$ to $10^{24} \mathrm{cm^{-3}}$ and the electron temperature is moderately higher than the Fermi energy

Plasmon band gap generated by intense ion acoustic waves

In the presence of an intense ion acoustic wave, the energy-momentum dispersion relation of plasmons is strongly modified to exhibit a band gap structure. The intensity of an ion acoustic wave might be measured from the band gap width. The plasmon band gap can be used to block the nonlinear cascading channel of Langmuir wave decayComment: 3 pages, 3 figures, published on Po

Hard x-ray or gamma ray laser by a dense electron beam

A coherent x-ray or gamma ray can be created from a dense electron beam propagating through an intense laser undulator. It is analyzed by using the Landau damping theory which suits better than the conventional linear analysis for the free electron laser, as the electron beam energy spread is high. The analysis suggests that the currently available physical parameters would enable the generation of the coherent gamma ray of up to 100 keV. The electron quantum diffraction suppresses the FEL action, by which the maximum radiation energy to be generated is limited

Entropy Maximization and Instability of Uniformly Magnetized Plasma

A regime where a uniformly magnetized plasma could be unstable to a spatial perturbation in the magnetic field is explored. In this regime, a uniformly magnetized state does not maximize the entropy. The physical implication is discussed in the context of the current generation, the magnetic reconnection, and the dynamo effect