43,599 research outputs found
Laser Pulse Propagation in Plasmas and its Implication on Frequency Up-shift and Electron Acceleration
This thesis documents the study of elementary processes in interaction of intense, ultrashort
laser pulses with underdense plasmas. Main objective of this thesis is to understand the
basic phenomena resulting from the interaction of ultra-short ultra-intense laser pulses with
matter and to study the mechanism which eventually leads to generation of high energetic
electrons, in laser based plasma accelerators. In a broad prospective, the work here can be
described as a detailed experimental and numerical study of laser matter interaction, plasma formation and acceleration of particles. The motivation for these experiments arises from
the fact that the results are relevant from both fundamental and applied research point of
view
The laser-matter interaction meets the high energy physics: Laser-plasma accelerators and bright X/gamma-ray sources
Laser matter interaction in the regime of super-intense and ultra-short laser pulses is discovering common interests and goals for plasma and elementary particles physics. Among them, the electron laser wakefield acceleration and the X/γ tunable sources, based on the Thomson scattering (TS) of optical photons on accelerated electrons, represent the most challenging applications. The activity of the Intense Laser Irradiation Laboratory in this field will be presented
Laser-like X-ray Sources Based on Optical Reflection from Relativistic Electron Mirror
A novel scheme is proposed to generate uniform relativistic electron layers
for coherent Thomson backscattering. A few-cycle laser pulse is used to produce
the electron layer from an ultra-thin solid foil. The key element of the new
scheme is an additional foil that reflects the drive laser pulse, but lets the
electrons pass almost unperturbed. It is shown by analytic theory and by 2D-PIC
simulation that the electrons, after interacting with both drive and reflected
laser pulse, form a very uniform flyer freely cruising with high relativistic
gamma-factor exactly in drive laser direction (no transverse momentum). It
backscatters probe light with a full Doppler shift factor of 4*gamma^2. The
reflectivity and its decay due to layer expansion is discussed.Comment: 5 pages, 3 figures, submitted, invited talk on the workshop of
Frontiers in Intense Laser-Matter Interaction Theory, MPQ, March 1-3, 2010
Direct laser acceleration of electrons in free-space
Compact laser-driven accelerators are versatile and powerful tools of
unarguable relevance on societal grounds for the diverse purposes of science,
health, security, and technology because they bring enormous practicality to
state-of-the-art achievements of conventional radio-frequency accelerators.
Current benchmarking laser-based technologies rely on a medium to assist the
light-matter interaction, which impose material limitations or strongly
inhomogeneous fields. The advent of few cycle ultra-intense radially polarized
lasers has materialized an extensively studied novel accelerator that adopts
the simplest form of laser acceleration and is unique in requiring no medium to
achieve strong longitudinal energy transfer directly from laser to particle.
Here we present the first observation of direct longitudinal laser acceleration
of non-relativistic electrons that undergo highly-directional multi-GeV/m
accelerating gradients. This demonstration opens a new frontier for direct
laser-driven particle acceleration capable of creating well collimated and
relativistic attosecond electron bunches and x-ray pulses
Instrumentation for ultra-intense laser matter interaction studies at high repetition rates
Includes bibliographical references.2022 Fall.A new class of high-repetition rate (HRR) Peta-Watt-class (PW) laser systems make it possible to study laser matter interaction processes, like laser ion acceleration (LIA) and laser plasma instabilities (LPI), at unprecedented rates. These systems have the potential to generate immense amounts of data through rapid multivariable parameters scans of laser energy, pulse shape, spot size and others, in order to better diagnose and characterize the conditions underlying LPI and LIA. However, detection media, typically image plates, film, CR-39, presently limits the repetition rate at which data can be collected from these systems. Rep-rated diagnostics are being redesigned to match the capabilities of current multi-Hz present and near future, PW-class laser systems. Here we present the development of a compact Thomson Parabola Ion Spectrometer capable of characterizing various ion species of multi-MeV ion beams from >10^20 W/cm^2 laser produced plasmas at rates commensurate with the laser operation rates. This diagnostic makes use of a Polyvinyltoluene (PVT) based fast plastic scintillator (EJ-260), where the emitted light is collected by an optical imaging system coupled to a thermoelectrically cooled scientific complementary metal–oxide–semiconductor (sCMOS) camera. This offers a robust solution for data acquisition at HRR while avoiding the added complications and non-linearities of microchannel plate (MCP) based systems. Different ion energy ranges can be probed using the modular magnet setup, variable electric field, and a varying drift-distance. We have demonstrated operation and data collection with this system at up to 0.2 Hz from plasmas created by irradiating a solid target, limited only by the motorized target motion system. With the appropriate software and the use of machine learning techniques, on-the-fly ion spectral analysis will be possible, enabling real-time experimental control. The diagnostic design, calibration, and results from experiments at the ALEPH laser facility at Colorado State University (CSU) are presented. In addition, we describe the results of the development of a novel scheme for the generation of spike trains of uneven delay (STUD) laser pulses using an array of hexagonal mirrors. By individually driving the offset of each mirror segment, we can divide the wavefront of the laser creating a pulse train of arbitrary delay. This pulse-train forming device can be used to conduct experiments related to a proposed method of mitigating the effects of LPI for inertial confinement fusion (ICF). By periodically turning on and off the laser drive of the ICF process, it has been postulated that the growth of parametric instabilities can be mitigated by allowing damping during the off-cycle of the STUD pulses. The use of the pulse-train forming scheme demonstrated here will allow us to study the effects of pulse train delay and duration best suited to LPI mitigation
- …