Stimulated compton scattering of surface plasma wave excited over metallic surface by a laser

A high-frequency surface plasma wave (SPW) excited over metallic surface irradiated by a laser beam, can undergo stimulated Compton scattering if phase velocity of daughter plasma wave is equal to the Fermi velocity for metal. The pump SPW${\rm (}{{\rm \omega} _0},{\vec k_{0{\rm z}}})$parametrically excites a quasi-electrostatic plasma wave${\rm (\omega}, {\vec k_{\rm z}})$and a backscattered sideband SPW${\rm (}{{\rm \omega} _1},{\vec k_{1{\rm z}}})$at resonance ω0= ω − ω1and${\vec k_{0{\rm z}}} = {\vec k_{\rm z}} - {\vec k_{1{\rm z}}}$. The growth rate of Compton process increases with the frequency of incident laser and turns out to be 5.425 × 1010rad/s at laser frequency ω0= 0.7595 × 1015rad/s for incident laser amplitudeA0L= 11 × 1011V/m, laser spot size b = 1.38 × 10−5m, and free electron density of metaln0= 5.85 × 1028/m3. The excitation of highly damped quasi-electrostatic plasma wave in this parametric process provide a better nonlinear option for surface heating as compared with direct laser heating. The process can also be used for diagnostics purposes.

Steady nonlinear electrostatic plasma wave in a weak transverse magnetic field

The structure of a stationary electrostatic plasma wave propagating at a right angle to a weak magnetic field is studied. It is shown that the periodic finite amplitude wave is close in its physical structure to Bernstein–Greene–Kruskal wave of a perfectly definite type. The distinguishing feature of such a nonlinear wave is the absence of the resonant particles trapped by the wave. The electron distribution function, density perturbation and the shape of the wave electrostatic potential are found. The nonlinear dispersion relation is derived to determine the frequency shift due to the perturbation of the distribution function in the resonant region.

Chaotic behavior of resonant absorption in the microwave range

The nonlinear evolution of electrostatic plasma waves excited by mode conversion is studied in an inhomogeneous, collisionless, unmagnetized plasma. Experiments in the microwave range (f = 3.5 GHz), performed in a plasma (ne ≃ 1011 cm−3) created in a multipolar discharge, show that the electrostatic plasma-wave evolution exhibits a transition from a nonlinear steady-state regime toward chaos, occurring when the pump field or the gradient length is increased. The Zakharov equations, which model the plasmawave evolution coupled with low-density perturbation, are solved numerically with parameters close to those of the experiment; this simulation allows a characterization of the two regimes.