We present a kinetic theory analysis of the electrostatic ion cyclotron (EIC) instability in a plasma containing positive ions, electrons, and negative ions that are much more massive than the positive ions. Conditions are investigated for exciting the fundamental and the higher harmonic EIC waves associated with each ion species. We find that as the concentration of heavy negative ions increas...

We have developed a diode-pumped Nd:YVO4 cw laser for testing KTiOPO4 crystals designed for intracavity second-harmonic generation at 532 nm. We demonstrate that this source is extremely sensitive to defects inside the crystal, inducing losses at 1064 nm and an index mismatch between fundamental and harmonic waves.

We report quasi-phase-matched second-harmonic generation in periodically poled lithium niobate (PPLN), where both fundamental and second-harmonic waves are ordinary waves. It provides a lower-limit value for d22 of 1.1 pm/V. The measured temperature and wavelength bandwidth of the second-harmonic signal are in good agreement with the theoretical predictions. Since the d22 = dYYY nonlinear coeff...

The pyrochlore lattice Heisenberg antiferromagnet has a massive classical ground state degeneracy. We summarize three approximation schemes, valid for large spin length S, to capture the (partial) lifting of this degeneracy when zero-point quantum fluctuations are taken into account; all three are related to analytic loop expansions. The first is harmonic order spin waves; at this order, there ...

The process of type II second-harmonic generation has been investigated theoretically. It is found that, unlike in the process of type I second-harmonic generation, phase matching is not necessary for a significant shift of the pump wave phase to be produced. The simple inequality of the intensities of interacting waves suffices for this effect to occur.

We analyze second-harmonic generation (SHG) at a thin effectively quadratic nonlinear interface between two linear optical media. We predict multistability of SHG for both plane and localized waves, and also describe two-color localized photonic modes composed of a fundamental wave and its second harmonic coupled together by parametric interaction at the interface.

The generation of internal gravity waves by tidal flow over topography is an important oceanic process that redistributes tidal energy in the ocean. Internal waves reflect from boundaries, creating harmonics and mixing. We use laboratory experiments and two-dimensional numerical simulations of the Navier–Stokes equations to determine the value of the topographic slope that gives the most intens...

When a high harmonic is removed from a cosine-phase harmonic complex, we hear a sine tone pop out of the perception; the sine tone has the pitch of the high harmonic, while the tone complex has the pitch of its fundamental frequency, f0. This phenomenon is commonly referred to as Duifhuis Pitch (DP). This paper describes, for the first time, the cortical representation of DP observed with magne...

We demonstrate the simultaneous generation and internal interference of two second-order parametric processes in a single nonlinear quadratic crystal. The two-frequency doubling processes are Type 0 (two extraordinary fundamental waves generate an extraordinary second-harmonic wave) and Type I (two ordinary fundamental waves generate an extraordinary second-harmonic wave) parametric interaction...

This study is motivated by the need to understand the elastodynamic response of belts in frictional contact with pulleys. To this end, a simplified model for belt~pulley contact is used to investigate the dynamic response of a belt subject to a train of harmonic tension waves. Through a nondimensionalization, a single dimensionless parameter f~ is identified which governs the dynamic response. ...