GeV acceleration in tapered plasma channels

To achieve multi GeV electron energies in the laser wakefield accelerator (LWFA) it is necessary to propagate an intense laser pulse long distances in a plasma without disruption. A three-dimensional envelope equation for the laser field is derived that includes nonparaxial effects, wakefields, and relativistic nonlinearities. In the broad beam, short pulse limit the nonlinear terms in the wave equation that lead to Raman and modulation instabilities cancel. Long pulses (several plasma wavelengths) experience substantial modification due to these instabilities. The short pulse LWFA, although having smaller accelerating fields, can provide acceleration for longer distances in a plasma channel. By allowing the plasma density to increase along the propagation path electron dephasing can be deferred, increasing the energy gain. A simulation example of a GeV channel guided LWFA accelerator is presented. Simulations also show that multi-GeV energies can be achieved by optimally tapering the plasma channel.

[1]  W. Mori,et al.  Seeding of the forward Raman instability by ionization fronts and Raman backscatter. , 2001, Physical review. E, Statistical, nonlinear, and soft matter physics.

[2]  P. Sprangle,et al.  Guiding and stability of short laser pulses in partially stripped ionizing plasmas , 1999 .

[3]  P. Sprangle,et al.  Plasma channel formation and guiding during high intensity short pulse laser plasma experiments , 1997 .

[4]  Thomas M. Antonsen,et al.  Kinetic modeling of intense, short laser pulses propagating in tenuous plasmas , 1997 .

[5]  S. V. Bulanov,et al.  Particle injection into the wave acceleration phase due to nonlinear wake wave breaking , 1998 .

[6]  Variable profile capillary discharge for improved phase matching in a laser wakefield accelerator , 1999 .

[7]  Zulfikar Najmudin,et al.  Observation of Electron Energies Beyond the Linear Dephasing Limit from a Laser-Excited Relativistic Plasma Wave , 1998 .

[8]  Esarey,et al.  Hose-Modulation Instability of Laser Pulses in Plasmas. , 1994, Physical review letters.

[9]  Eric Esarey,et al.  Overview of plasma-based accelerator concepts , 1996 .

[10]  D. Gordon,et al.  Wakefield generation and GeV acceleration in tapered plasma channels. , 2001, Physical review. E, Statistical, nonlinear, and soft matter physics.

[11]  Donald P. Umstadter,et al.  Physics and Applications of Relativistic Plasmas Driven by Ultra-intense Lasers , 2001 .

[12]  Warren B. Mori,et al.  The Physics of the Nonlinear Optics of Plasmas at Relativistic Intensities , 1996 .

[13]  Hubbard,et al.  Relativistic focusing and ponderomotive channeling of intense laser beams , 2000, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[14]  P. Audebert,et al.  Monomode Guiding of 10 16 W/cm 2 Laser Pulses over 100 Rayleigh Lengths in Hollow Capillary Dielectric Tubes , 1999 .

[15]  Eric Esarey,et al.  Guiding of laser pulses in plasma channels created by the ignitor-heater technique , 1999 .

[16]  P. Sprangle,et al.  Measurements of energetic electrons from the high-intensity laser ionization of gases , 2001 .

[17]  Sprangle,et al.  Laser pulse modulation instabilities in plasma channels , 2000, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[18]  Laser-induced electron trapping in plasma-based accelerators , 1999 .

[19]  Esarey,et al.  Nonlinear interaction of intense laser pulses in plasmas. , 1989, Physical review. A, Atomic, molecular, and optical physics.

[20]  T. Clark,et al.  Development and applications of a plasma waveguide for intense laser pulses , 1996 .

[21]  Thomas M. Antonsen,et al.  Numerical simulation of short laser pulse relativistic self-focusing in underdense plasma , 1998 .

[22]  Production And Characterization Of A Fully-Ionized He Plasma Channel , 2000 .

[23]  Wurtele,et al.  Nonlinear theory of nonparaxial laser pulse propagation in plasma channels , 1999, Physical review letters.

[24]  K. Nakajima,et al.  Structure of the wake field in plasma channels , 1997 .

[25]  Eric H. Esarey,et al.  Laser wakefield acceleration and relativistic optical guiding , 1988 .

[26]  Duda,et al.  Variational principle approach to short-pulse laser-plasma interactions in three dimensions , 2000, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[27]  Mode control in a two-pulse-excited plasma waveguide , 1996 .

[28]  Mora,et al.  Self-focusing and Raman scattering of laser pulses in tenuous plasmas. , 1992, Physical review letters.

[29]  Decker,et al.  Group velocity of large amplitude electromagnetic waves in a plasma. , 1995, Physical review letters.

[30]  Govind P. Agrawal,et al.  Nonlinear Fiber Optics , 1989 .

[31]  T. Katsouleas,et al.  Physical mechanisms in the plasma wake-field accelerator. , 1986, Physical review. A, General physics.

[32]  Observation of Raman forward scattering and electron acceleration in the relativistic regime , 1996 .