Several aspects of the beam-cavity interaction were investigated in a beam test of the superconducting accelerating cavity module for the CESR upgrade: the time structure of the cavity wake potential, sampled with two bunches, the effect of the module on the total machine loss factor, and the influence of the cavity tuner position on the frequencies and damping times of coupled bunch modes. The...

Plasma wakefields are both excited and probed by propagating an intense 28.5 GeV positron beam through a 1.4 m long lithium plasma. The main body of the beam loses energy in exciting this wakefield while positrons in the back of the same beam can be accelerated by the same wakefield as it changes sign. The scaling of energy loss with plasma density as well as the energy gain seen at the highest...

The mesh-excited space charge wave of ion beam is observed to be amplified in a plasma, as the result of the reactivemedium instability. The amplification factor has the maximum value at the frequency corresponding to the synchronization condition between the beam wave and the lower hybrid wave mode of plasma, and then, an appreciable deceleration of beam is expected from the observation of the...

A novel diagnostic method for detecting ordering in one-dimensional ion beams is presented. The ions are excited by a pulsed laser at two different positions along the beam and fluorescence is observed by a group of four photomultipliers. Correlation in fluorescence signals is firm indication that the ion beam has an ordered structure.

The energy deposition of a relativistic electron beam in a plasma can be managed through turning on or off fast beam-plasma instabilities in desirable regions. This management may enable new ways of realizing the fast-igniter scenario of inertial fusion. Collisional effects alone can decelerate electrons of at most a few MeV within the core of an inertial-fusion target. Beam-excited Langmuir tu...

In the last decade we have witnessed exciting technological advances in the fabrication and control of microelectromechanical and nanoelectromechanical systems (MEMS&NEMS) [16, 19, 26, 54, 55]. Such systems are being developed for a host of nanotechnological applications, such as highly sensitive mass [25, 34, 67], spin [56], and charge detectors [17, 18], as well as for basic research in the m...

As is known, a totally reflected beam experiences a lateral displacement from its position predicted by the geometric optics because each of its plane-wave components undergoes a different phase change [1]. For the beam reflected from an interface, the lateral beam shift (the so-called Goos-Hänchen effect) is usually much less than the beam width. However, larger beam shifts may occur in the la...

This paper studies the characteristics of horizontal resonances excited by the beam-beam interaction. First order perturbation theory and simulations show that high order horizontal resonances are exceptionally strong at large amplitudes. The orders of these resonances are so high that they may mistakenly be ignored, and they can result in bad lifetime.

The nonlinear interactions of parametrically excited surface waves have been shown to yield a rich family of nonlinear states. When the system is driven by two commensurate frequencies, a variety of interesting superlattice type states are generated via a number of different 3-wave resonant interactions. These states occur either as symmetrybreaking bifurcations of hexagonal patterns composed o...

A pair of coupled gold nanorods excited by a beam of free electrons acts as a transmitting Hertzian antenna in the optical part of the spectrum. Significantly enhanced resonant emission is observed from the antenna when the electron beam is injected around the junction between the rods, where the local density of electromagnetic states is elevated.