The plasma afterburner has been proposed as a possible advanced acceleration scheme for a future linear collider. In this concept, a high energy electron(or positron) drive beam from an existing linac such as the SLC will propagate in a plasma section of density about one order of magnitude lower than the peak beam density. The particle beam generates a strong plasma wave wakefield which has a ...

Understanding of space charge effects has grown and recent studies have led to the findings of space charge resonances in high intensity linear accelerators. Lately the sixth order resonance of high intensity linear accelerators was reported, along with the in-depth studies on the interplay of the fourth order resonance and the envelope instability. Experiment studies on space charge resonances...

The introduction of a plasma and a strong guide magnetic field in a free electron laser (FEL) slows down the phase velocity of radiation, significantly reducing the requirements on beam energy for generating frequencies below the electron-cyclotron frequency (oi, < oj,). Around plasma resonance (cu, ~ wp), the FEL mode couples to two-stream instability (TSI), attaining a large growth rate, comp...

We provide what is to our knowledge the first experimental evidence that multiple filamentation (MF) of ultra-short pulses can be induced by input beam ellipticity. Unlike noise-induced MF, which results in complete beam breakup, the MF pattern induced by small input beam ellipticity appears as a result of nucleation of annular rings surrounding the central filament. Moreover, our experiments s...

A 200-eV electron beam is incident on an electrode in a laboratory plasma. The emission of secondary electrons produces a region of negative differential resistance in the current-voltage characteristic of the electrode. Spontaneous dynatron oscillations are driven by the negative differential resistance when a resonant circuit is placed in series with the electrode. The instability is driven b...

The high quality LCLS electron beam generated in the photoinjector is subject to many instabilities in the downstream acceleration and compression. The instability can be initiated by any density modulation of the electron beam generated at the photocathode. In this paper, we prescribe the tolerance on the initial electron beam density modulation possibly introduced by the ultraviolet (uv) lase...

Initial operating experience witll the SLAC electronpositron storage ring SPEAR is described. A luminosity of 1.2 x 1031 cm-2 set-I has been achieved and two-beam interaction effects are described. A single-beam coherent instability, which can be suppressed either by control of the ring chromaticity or by feedback, has been observed. Current-dependent bunch lengthening and widening have been ob...

An anomalous damping or growth of transverse coupled bunch modes is observed in CESR. The growth rates and tune shifts of these modes are a highly nonlinear function of current. The effect is associated with the operation of the distributed ion pumps and disappears when the pumps are not powered. We show that this effect is due to the presence of electrons trapped in the CESR chamber by the fie...

– We present an investigation of the electromagnetic instabilities which are triggered when an ultra relativistic electron beam passes through a plasma. The linear growth rate is computed for every direction of propagation of the unstable modes, and temperatures are modelled using simple waterbag distribution functions. The ultra relativistic unstable spectrum is located around a very narrow ba...

The Budker-Chirikov instability (BCI) in a two-beam electron-ion system is researched. The BCI is due to the interaction of the slow cyclotron wave of the electron beam with the fast betatron wave of the ion beam. The electron-ion system consists of a high current relativistic electron beam propagating co-axially with a nonrelativistic ion beam in a drift tube. The external radii of the electro...