229 research outputs found
Laser acceleration of protons from near critical density targets for application to radiation therapy
Laser accelerated protons can be a complimentary source for treatment of
oncological diseases to the existing hadron therapy facilities. We demonstrate
how the protons, accelerated from near-critical density plasmas by laser pulses
having relatively small power, reach energies which may be of interest for
medical applications. When an intense laser pulse interacts with near-critical
density plasma it makes a channel both in the electron and then in the ion
density. The propagation of a laser pulse through such a self-generated channel
is connected with the acceleration of electrons in the wake of a laser pulse
and generation of strong moving electric and magnetic fields in the propagation
channel. Upon exiting the plasma the magnetic field generates a quasi-static
electric field that accelerates and collimates ions from a thin filament formed
in the propagation channel. Two-dimensional Particle-in-Cell simulations show
that a 100 TW laser pulse tightly focused on a near-critical density target is
able to accelerate protons up to energy of 250 MeV. Scaling laws and optimal
conditions for proton acceleration are established considering the energy
depletion of the laser pulse.Comment: 25 pages, 8 figure
Laser-driven high-power X- and gamma-ray ultra-short pulse source
A novel ultra-bright high-intensity source of X-ray and gamma radiation is
suggested. It is based on the double Doppler effect, where a relativistic
flying mirror reflects a counter-propagating electromagnetic radiation causing
its frequency multiplication and intensification, and on the inverse double
Doppler effect, where the mirror acquires energy from an ultra-intense
co-propagating electromagnetic wave. The role of the flying mirror is played by
a high-density thin plasma slab accelerating in the radiation pressure dominant
regime. Frequencies of high harmonics generated at the flying mirror by a
relativistically strong counter-propagating radiation undergo multiplication
with the same factor as the fundamental frequency of the reflected radiation,
approximately equal to the quadruple of the square of the mirror Lorentz
factor.Comment: 8 pages, 5 figures. Presented at the ELI Workshop and School on
"Fundamental Physics with Ultra-High Fields" 29.09.-02.10.2008, in
Frauenworth Monastery, Bavaria, German
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