The transverse beam dynamics in plasma channels of possible future plasma-based linacs is discussed. We represent the transverse focusing of both a beam-driven and a laser-driven plasma wake eld accelerator by a uniform focusing channel. The transverse beam sizes and a basic o set tolerance are calculated, nding that sub-micron beams must be transported with even smaller o set tolerances. The r...

The possibility of producing ultrashort (fs) X-ray pulses through Thomson scattering of high power laser pulses off relativistic electron bunches generated by plasma-based accelerators is discussed. The electron bunches are produced with either a self-modulated laser wakefield accelerator (SM-LWFA) or through a standard laser wakefield accelerator (LWFA) with optical injection. For a SM-LWFA (L...

Warm Dense Matter (WDM) is a challenging science field, which is related to heavy ion inertial fusion and planetary science. It is difficult to expect the behavior because the state with high density and low temperature is completely different from ideal condition. The well-defined WDM generation is required to understand it. Moderate energy ion beams (∼ MeV/u) slightly above Bragg peak is an a...

The electron acceleration, in a laser wakefield accelerator, controlled through plasma density inhomogeneity is studied on basis of 2.5-dimensional particle-in-cell simulation. acceleration requires concordance the scale length and shift accelerated bunch relative to wake bubble during acceleration. This paper considers excitation with equal free electrons metals, solid-state (the original idea...

To achieve multi-GeV electron energies in the laser wakefield accelerator (LWFA) it is necessary to propagate an intense laser pulse long distances in plasma without disruption. A 3D envelope equation for a laser pulse in a tapered plasma channel is derived, which includes wakefields and relativistic and nonparaxial effects, such as finite pulse length and group velocity dispersion. It is shown...

We present initial experimental results showing the excitation of plasma wakefields by a train of two drive bunches. These wakefields are experienced by a trailing witness bunch that gains energy while retaining a finite energy spread. These well controlled plasma wakefield accelerator (PWFA) experiments are important to test the theory of the PWFA and serve as a testbed for techniques that wil...

The acceleration and deceleration of photons m a plasma provides the means lbr a series of new radiation sources. Previous work on a DC to AC Radiation Converter (DARC source) has shown variable acceleration of photons having zero frequency (i.e., an electrostatic field) to belx~een 6 and 100 GHz (I-3). These sources all had poor guiding characteristics resulting in poor power coupling froln th...

In this paper we describe the recent work at UCLA on the acceleration of externally injected electrons by a relativistic plasma wave. A two frequency laser was used to excite a plasma wave over a narrow range of static gas pressures close to resonance. Electrons with energies up to our detection limit of 9.1 MeV were observed when 2.1 MeV electrons were injected in the plasma wave. No accelerat...

We present few-femtosecond shadowgraphic snapshots taken during the nonlinear evolution of the plasma wave in a laser wakefield accelerator with transverse synchronized few-cycle probe pulses. These snapshots can be directly associated with the electron density distribution within the plasma wave and give quantitative information about its size and shape. Our results show that self-injection of...