We investigate the nonlinear optical properties of gold nanoparticle pairs. Two excitation beams of frequencies ω1 and ω2 are used to induce nonlinear polarizations at the junction of a particle dimer. Nonlinearities of the second and third order can be controllably induced as a function of the dimer geometry, leading predominantly to second-harmonic generation (SHG), sum frequency generation (...

We study wave propagation in a chain of spherical particles containing a local resonator. The resonant particles are made of an aluminum outer spherical shell and a steel inner mass connected by a polymeric plastic structure acting as a spring. We characterize the dynamic response of individual particles and the transmitted linear spectra of a chain of particles in contact. A wide band gap is o...

Using the quasi-particle approach, we studied the problem of the reflection of quadratic spatial solitons from an interface between two x (2) media with slightly different linear and nonlinear properties. The possibility of soliton capture by an interface associated with nonlinear surface wave excitation is shown. The calculations are carried out for the well-known single as well as a novel typ...

We study the generation of nonlinear plasma wake fields by intense laser pulses, using an Eulerian code for the numerical solution of the fully relativistic onedimensional (1D) Vlasov-Maxwell equations. The examination of the phase-space of the distribution function allows to study without numerical noise aspects of the particle acceleration by the wake-field generated by intense laser pulses, ...

Precise variational solutions are given for problems involving diverse fermionic and bosonic N = 2−7-body systems. The trial wave functions are chosen to be combinations of correlated Gaussians, which are constructed from products of the single-particle Gaussian wave packets through an integral transformation, thereby facilitating fully analytical calculations of the matrix elements. The nonlin...

Global gyrokinetic particle simulation and nonlinear gyrokinetic theory find that electron temperature gradient sETGd instability saturates via nonlinear toroidal coupling, which is a nonlocal interaction in the wave vector space that transfers energy successively from unstable modes to damped modes preferentially with lower toroidal mode numbers. The electrostatic ETG turbulence is dominated b...

Precise variational solutions are given for problems involving diverse fermionic and bosonicN = 2 7-body systems. The trial wave functions are chosen to be combinations of correlated Gaussians, which are constructed from products of the single-particle Gaussian wave packets through an integral transformation, thereby facilitating fully analytical calculations of the matrix elements. The nonline...

A fast Alfvén wave with a finite amplitude is shown to grow by a stimulated emission process that we propose for exploitation in toroidal magnetically confined fusion plasmas. Stimulated emission occurs while the wave propagates inward through the outer midplane plasma, where a population inversion of the energy distribution of fusion-born ions is observed to arise naturally. Fully nonlinear fi...

We model strong forward shocks in young supernova remnants with efficient particle acceleration where a nonresonant instability driven by the cosmic ray current amplifies magnetic turbulence in the shock precursor. Particle injection, magnetic field amplification (MFA) and the nonlinear feedback of particles and fields on the bulk flow are derived consistently. The shock structure depends criti...