13 research outputs found
Ion Acceleration by Short Chirped Laser Pulses
Direct laser acceleration of ions by short frequency-chirped laser pulses is
investigated theoretically. We demonstrate that intense beams of ions with a
kinetic energy broadening of about 1 % can be generated. The chirping of the
laser pulse allows the particles to gain kinetic energies of hundreds of MeVs,
which is required for hadron cancer therapy, from pulses of energies of the
order of 100 J. It is shown that few-cycle chirped pulses can accelerate ions
more efficiently than long ones, i.e. higher ion kinetic energies are reached
with the same amount of total electromagnetic pulse energy
Feasibility of electron cyclotron autoresonance acceleration by a short terahertz pulse
A vacuum autoresonance accelerator scheme for electrons, which employs
terahertz radiation and currently available magnetic fields, is suggested.
Based on numerical simulations, parameter values, which could make the scheme
experimentally feasible, are identified and discussed
Attosecond gamma-ray pulses via nonlinear Compton scattering in the radiation dominated regime
The feasibility of generation of bright ultrashort gamma-ray pulses is
demonstrated in the interaction of a relativistic electron bunch with a
counterpropagating tightly-focused superstrong laser beam in the radiation
dominated regime. The Compton scattering spectra of gamma-radiation are
investigated using a semiclassical description for the electron dynamics in the
laser field and a quantum electrodynamical description for the photon emission.
We demonstrate the feasibility of ultrashort gamma-ray bursts of hundreds of
attoseconds and of dozens of megaelectronvolt photon energies in the
near-backwards direction of the initial electron motion. The tightly focused
laser field structure and radiation reaction are shown to be responsible for
such short gamma-ray bursts which are independent of the durations of the
electron bunch and of the laser pulse. The results are measurable with the
laser technology available in a near-future
Laser-generated Ion Beams for Medical Applications
The advent of high-power laser systems paved the way for laser acceleration of ion beams. Based on theoretical simulations, we demonstrate the feasibility of laser-generated ion beams matching the strict requirements for radio-oncological applications. Particle energies of several hundred MeV and low energy spreads of 1% are feasible within the framework of direct laser acceleration. A mechanism is suggested to efficiently post-accelerate particle beams originating from laser-plasma interaction processes, where the injection of ions into the focus is modeled in a realistic way. Introducing a long-wavelength CO2 laser leads to an increase in the total number of particles accelerated as one bunch by three orders of magnitude as compared to lasers with a wavelength around 1 micro meter. By employing pulsed laser systems in a single- and a crossed-beams configuration, we show that ion beams of high particle numbers can be produced. In a different setting we put forward the interaction of a chirped laser pulse with a hydrogen gas target of spatial extension of the order of the laser wavelength studied by means of particle-in-cell simulations. The low frequency components of the laser pulse allow for generating clinically applicable beams already while interacting with state-of-the-art laser systems of intensities of 10^21 W/cm^2
High-quality multi-GeV electron bunches via cyclotron autoresonance
Autoresonance laser acceleration of electrons is theoretically investigated
using circularly polarized focused Gaussian pulses. Many-particle simulations
demonstrate feasibility of creating over 10-GeV electron bunches of ultra-high
quality (relative energy spread of order 10^-4), suitable for fundamental
high-energy particle physics research. The laser peak intensities and axial
magnetic field strengths required are up to about 10^18 W/cm^2 (peak power ~10
PW) and 60 T, respectively. Gains exceeding 100 GeV are shown to be possible
when weakly focused pulses from a 200-PW laser facility are used
Dense monoenergetic proton beams from chirped laser-plasma interaction
Interaction of a frequency-chirped laser pulse with single protons and a
hydrogen plasma cell is studied analytically and by means of particle-in-cell
simulations, respectively. Feasibility of generating ultra-intense (10^7
particles per bunch) and phase-space collimated beams of protons (energy spread
of about 1 %) is demonstrated. Phase synchronization of the protons and the
laser field, guaranteed by the appropriate chirping of the laser pulse, allows
the particles to gain sufficient kinetic energy (around 250 MeV) required for
such applications as hadron cancer therapy, from state-of-the-art laser systems
of intensities of the order of 10^21 W/cm^2.Comment: 5 pages, 4 figure
Intense high-quality medical proton beams via laser fields
During the past decade, the interaction of high-intensity lasers with solid
targets has attracted much interest, regarding its potential in accelerating
charged particles. In spite of tremendous progress in laser-plasma based
acceleration, it is still not clear which particle beam quality will be
accessible within the upcoming multi petawatt (1 PW = 10 W) laser
generation. Here, we show with simulations based on the coupled relativistic
equations of motion that protons stemming from laser-plasma processes can be
efficiently post-accelerated using crossed laser beams focused to spot radii of
a few laser wavelengths. We demonstrate that the crossed beams produce
monoenergetic accelerated protons with kinetic energies MeV, small
energy spreads ( 1) and high densities as required for hadron
cancer therapy. To our knowledge, this is the first scheme allowing for this
important application based on an all-optical set-up.Comment: 14 pages, 3 figures, 1 tabl