Novel techniques of laser acceleration: from structures to plasmas

Abstract

Compact accelerators of the future will require enormous accelerating gradients that can only be generated using high power laser beams. Two novel techniques of laser particle acceleration are discussed. The first scheme is based on a solid-state accelerating structure powered by a short pulse CO(2) laser. The planar structure consists of two SiC films, separated by a vacuum gap, grown on Si wafers. Particle acceleration takes place inside the gap by a surface electromagnetic wave excited at the vacuum/SiC interface. Laser coupling is accomplished through the properly designed Si grating. This structure can be inexpensively manufactured using standard microfabrication techniques and can support accelerating fields well in excess of 1 GeV m(-1) without breakdown. The second scheme utilizes a laser beatwave to excite a high-amplitude plasma wave, which accelerates relativistic particles. The novel aspect of this technique is that it takes advantage of the nonlinear bi-stability of the relativistic plasma wave to drive it close to the wavebreaking.

Relativistic Dynamical Bi-Stability of Plasma Waves in a Plasma Wakefield Accelerator

“…system of equations that can be rewritten in a canonical form for conjugate variables I = u 2 /2 and T with Hamiltonian (1), where b = 1 -Z (detuning), c = 3/16, and a = R [4,7].…”

“…[5,7] have revealed an important property of its phase space: depending on the values of a, b, and c, there are either one (elliptic) fixed point, or three (two elliptic, one hyperbolic) fixed points. [5,7] have revealed an important property of its phase space: depending on the values of a, b, and c, there are either one (elliptic) fixed point, or three (two elliptic, one hyperbolic) fixed points.…”

Electron acceleration by surface plasma waves in the presence of static magnetic field

“…In their follow-up experiments, 400 eV electrons were generated by exciting the SPWs with 0.8 mJ (40 TW/cm 2 ) laser pulses (Zawadzka et al, 2001). Kalmykov et al (2006) have studied SPW excitation on two parallel plane silicon carbide films separated by a vacuum region and discussed its potential for electron acceleration. Steinhauer and Kimura (2003) developed an elegant analytical formalism for surface wave propagation over two parallel conducting planes and on the inner boundary of a hollow cylinder to describe the potential of SPW for electron acceleration.…”

Equal energy phase space trajectories in resonant wave interactions

“…7 If the variation of parameters in the Hamiltonian ͑1͒ is slow, the underlying dynamics can be understood by studying the associated phase space structure for fixed parameters. [8][9][10] For example, depending on the values of parameters a, b, and c, one may encounter either one ͑elliptic͒ fixed point or three ͑two elliptic, one hyperbolic͒ fixed points in phase space. Therefore, the topology of the phase space evolution may change considerably by variation of system parameters and one may expect transition from small to large amplitude excitations because of this topological change.…”