Speaker
Description
Short directional X-rays have been extensively studied due to their high potential in many
applications such as high-quality phase-contrast imaging of biological samples and spectroscopy at
femtosecond timescale. Interaction of very intense laser pulses with plasma medium enables the
production of high energy photons in X- and gamma-ray range by several mechanisms, such as
betatron radiation, Compton scattering and bremmstahlung. A basic principle is that a relativistic
electron radiates light at a very short wavelength, which is a consequence of a relativistic Doppler
shift. In the frame of this project, the betatron radiation from laser wakefield acceleration (LWFA) of
electrons will be studied. In LWFA, electrons are injected into a plasma wave (wakefield), generated
and dragged by a few-tens-of-fs, ultra-intense laser pulse (driver) in optically transparent plasmas.
The betatron radiation is naturally generated due to the transverse oscillatory motion of electrons during the acceleration. In order to introduce LWFA X-ray sources fully for practical purposes, the production of more photons is required. To address this problem, plasma density modifications were examined. The process was studied for standard parameters feasible with current sub-100 TW laser systems by means of numerical particle-in-cell simulations. We show that the intensity of radiation increases when the plasma density increases.
