45 research outputs found
On extreme field limits in high power laser matter interactions: radiation dominant regimes in high intensity electromagnetic wave interaction with electrons
We discuss the key important regimes of electromagnetic field interaction
with charged particles. Main attention is paid to the nonlinear Thomson/Compton
scattering regime with the radiation friction and quantum electrodynamics
effects taken into account. This process opens a channel of high efficiency
electromagnetic energy conversion into hard electromagnetic radiation in the
form of ultra short high power gamma ray flashes.Comment: 15 pages, 10 figures, invited talk presented at the SPIE-2013
conference, Prague, Czech Republic, Apr. 15, 201
A compact, all-optical positron production and collection scheme
In this paper we discuss a compact, laser-plasma-based scheme for the
generation of positron beams suitable to be implemented in an all-optical
setup. A laser-plasma-accelerated electron beam hits a solid target producing
electron-positron pairs via bremsstrahlung. The back of the target serves as a
plasma mirror to in-couple a laser pulse into a plasma stage located right
after the mirror where the laser drives a plasma wave (or wakefield). By
properly choosing the delay between the laser and the electron beam the
positrons produced in the target can be trapped in the wakefield, where they
are focused and accelerated during the transport, resulting in a collimated
beam. This approach minimizes the ballistic propagation time and enhances the
trapping efficiency. The system can be used as an injector of positron beams
and has potential applications in the development of a future, compact,
plasma-based electron-positron linear collider
On the breaking of a plasma wave in a thermal plasma: I. The structure of the density singularity
The structure of the singularity that is formed in a relativistically large
amplitude plasma wave close to the wavebreaking limit is found by using a
simple waterbag electron distribution function. The electron density
distribution in the breaking wave has a typical "peakon" form. The maximum
value of the electric field in a thermal breaking plasma is obtained and
compared to the cold plasma limit. The results of computer simulations for
different initial electron distribution functions are in agreement with the
theoretical conclusions.Comment: 21 pages, 12 figure
Lorentz-Abraham-Dirac vs Landau-Lifshitz radiation friction force in the ultrarelativistic electron interaction with electromagnetic wave (exact solutions)
When the parameters of electron - extreme power laser interaction enter the
regime of dominated radiation reaction, the electron dynamics changes
qualitatively. The adequate theoretical description of this regime becomes
crutially important with the use of the radiation friction force either in the
Lorentz-Abraham-Dirac form, which possess unphysical runaway solutions, or in
the Landau-Lifshitz form, which is a perturbation valid for relatively low
electromagnetic wave amplitude. The goal of the present paper is to find the
limits of the Landau-Lifshitz radiation force applicability in terms of the
electromagnetic wave amplitude and frequency. For this a class of the exact
solutions to the nonlinear problems of charged particle motion in the
time-varying electromagnetic field is used.Comment: 14 pages, 5 figure
Low transverse emittance electron bunches from two-color laser-ionization injection
A method is proposed to generate low emittance electron bunches from two
color laser pulses in a laser-plasma accelerator. A two-region gas structure is
used, containing a short region of a high-Z gas (e.g., krypton) for ionization
injection, followed by a longer region of a low-Z gas for post-acceleration. A
long-laser-wavelength (e.g., 5 micron) pump pulse excites plasma wake without
triggering the inner-shell electron ionization of the high-Z gas due to low
electric fields. A short-laser-wavelength (e.g., 0.4 micron) injection pulse,
located at a trapping phase of the wake, ionizes the inner-shell electrons of
the high-Z gas, resulting in ionization-induced trapping. Compared with a
single-pulse ionization injection, this scheme offers an order of magnitude
smaller residual transverse momentum of the electron bunch, which is a result
of the smaller vector potential amplitude of the injection pulse
Generation of GeV protons from 1 PW laser interaction with near critical density targets
The propagation of ultra intense laser pulses through matter is connected
with the generation of strong moving magnetic fields in the propagation channel
as well as the formation of a thin ion filament along the axis of the channel.
Upon exiting the plasma the magnetic field displaces the electrons at the back
of the target, generating a quasistatic electric field that accelerates and
collimates ions from the filament. Two-dimensional Particle-in-Cell simulations
show that a 1 PW laser pulse tightly focused on a near-critical density target
is able to accelerate protons up to an energy of 1.3 GeV. Scaling laws and
optimal conditions for proton acceleration are established considering the
energy depletion of the laser pulse.Comment: 26 pages, 8 figure
A Laser-Plasma Ion Beam Booster Based on Hollow-Channel Magnetic Vortex Acceleration
Laser-driven ion acceleration can provide ultra-short, high-charge,
low-emittance beams. Although undergoing extensive research, demonstrated
maximum energies for laser-ion sources are non-relativistic, complicating
injection into high- accelerator elements and stopping short of
desirable energies for pivotal applications, such as proton tumor therapy. In
this work, we decouple the efforts towards relativistic beam energies from a
single laser-plasma source via a proof-of-principle concept, boosting the beam
into this regime through only a few plasma stages. We employ full 3D
particle-in-cell simulations to demonstrate the capability for capture of
high-charge beams as produced by laser-driven sources, where both source and
booster stages utilize readily available laser pulse parameters.Comment: 4 pages, 4 figures, submitted for peer revie