scholarly journals WEDGE-SHAPED JET PLASMA FOR RAMAN COMPRESSION OF LASER PULSES

2019 ◽  
Vol 47 (1) ◽  
pp. 18-20
Author(s):  
A.A. Balakin ◽  
S. A. Skobelev ◽  
G. M. Fraiman
Keyword(s):  
High Efficiency ◽  
Laser Pulses ◽  
High Energy ◽  
Intense Laser ◽  
Energy Output ◽  
Gas Jet ◽  
Nonlinear Frequency ◽  
Jet Plasma ◽  
Stimulated Raman Backscattering ◽  
Stimulated Raman

Two processes of shortening an intense laser pulse are discussed in a transparent plasma: self-compression at wake wave excitation (Balakin et. al, 2013) and at stimulated Raman backscattering (Malkin et. al, 1999). Studying the possibility of amplification and compression of ultrashort (up to several field periods) laser pulses in a plasma based on the process of stimulated Raman backscattering is an important task aimed at creating next-generation superpower laser systems that generate ultrashort petawatt and exawatt laser pulses. However, there is a number of negative physical processes that may limit the effectiveness of Raman amplification. Most of these negative processes have been studied and ways are suggested to neutralize them. Among the most dangerous is the nonlinear frequency shift near the threshold for the overturning of the plasma wave (Balakin et. al, 2018). The use of a highly inhomogeneous jet plasma gives a significant density gradient along the jet. Accordingly, it is possible to compensate an excessively large frequency modulation of the pump due to the use of density inhomogeneity along the gas jet. In this case, Raman compression occurs without a significant loss of energy efficiency. Using a nozzle for a gas jet in the form of a long slit allows one create a long and uniform plasma in one of the directions having a wedge shape. The possibility of obtaining a high-energy output signal using wide-aperture laser pulses in a wedge-shaped plasma is predicted. Optimal parameters of the gas jet and laser pulses are proposed to ensure high efficiency and focusability, close to the ideal case. This research was supported by the Russian Science Foundation (Project 17-72-20111).

scholarly journals Concept of generation of extremely compressed high-energy electron bunches in several interfering intense laser pulses with tilted amplitude fronts

2012 ◽  
Vol 31 (1) ◽  
pp. 23-28 ◽  
Author(s):  
V.V. Korobkin ◽  
M.Yu. Romanovskiy ◽  
V.A. Trofimov ◽  
O.B. Shiryaev
Keyword(s):  
Laser Pulses ◽  
High Energy ◽  
Intense Laser ◽  
High Energy Electron ◽  
Speed Of Light ◽  
Electron Bunches ◽  
Newton Equation ◽  
High Energies ◽  
Neutral Gas ◽  
Intense Laser Pulses

AbstractA new concept of generating tight bunches of electrons accelerated to high energies is proposed. The electrons are born via ionization of a low-density neutral gas by laser radiation, and the concept is based on the electrons acceleration in traps arising within the pattern of interference of several relativistically intense laser pulses with amplitude fronts tilted relative to their phase fronts. The traps move with the speed of light and (1) collect electrons; (2) compress them to extremely high density in all dimensions, forming electron bunches; and (3) accelerate the resulting bunches to energies of at least several GeV per electron. The simulations of bunch formation employ the Newton equation with the corresponding Lorentz force.

scholarly journals Tc-99m production with ultrashort intense laser pulses

2014 ◽  
Vol 32 (4) ◽  
pp. 605-611 ◽  
Author(s):  
V. Yu. Bychenkov ◽  
A. V. Brantov ◽  
G. Mourou
Keyword(s):  
Laser Pulse ◽  
Thin Foil ◽  
Laser Pulses ◽  
High Energy ◽  
Intense Laser ◽  
Pic Simulation ◽  
Intense Laser Pulses ◽  
Fs Laser ◽  
Proton Generation ◽  
Coherent Amplification

AbstractThe interaction of a relativistic short laser pulse with thin foil is studied using 3D PIC simulations in the context of optimized high-energy proton generation for nuclear medicine and pharmacy. As an example, we analyze the Tc-99m yield from the Mo-100(p,2n)Tc-99m reaction with the International Coherent Amplification Network (ICAN) concept defined by a 10 J pulse energy and 10 kHz repetition rate. Based on 3D PIC simulation it has been demonstrated that normally incident 100 fs laser pulse with maximum intensity of 5 × 1021 W/cm2 is able to generate 1011 protons with energy upto 45 MeV from thin semi-transparent CH2 target. Such laser-produced proton beam after 6 hours bombardment of the thick metallic Mo-100 target gives around 300 Gbq activities of Tc-99m isotope. This gives reason to believe that laser technology for producing technetium is possible with ICAN concept to replace the traditional scheme through the fission of weapons-grade uranium.

scholarly journals Stimulated Raman scattering in plasmas produced by short intense laser pulses

1995 ◽  
Vol 13 (4) ◽  
pp. 525-537 ◽  
Author(s):  
H.C. Barr ◽  
T.J.M. Boyd ◽  
F.I. Gordon ◽  
S.J. Berwick
Keyword(s):  
Raman Scattering ◽  
Growth Rates ◽  
Stimulated Raman Scattering ◽  
Mode Conversion ◽  
Scattered Light ◽  
Laser Pulses ◽  
Laboratory Frame ◽  
Intense Laser ◽  
Strongly Coupled ◽  
Stimulated Raman

Stimulated Raman scattering driven by intense subpicosecond laser drivers is analyzed, in particular, the effects of the pulse shape and relativity on the instability and its characteristic spectra. The analysis is carried out in the pulse group velocity frame (Lorentz transformed) where growth rates for backscattering are decreased relative to their values when analyzed in the laboratory frame, while forward-scattered growth rates have greatly enhanced values. A range of intensities and densities is considered, appropriate to recent experiments, which ranges from strongly coupled scattering at high densities (even for forwardscattering) to stimulated Compton scattering regimes for backscattering and relativistically trapped forwardscattering at low densities. The inhomogeneities in intensity and density cause mode conversion between waves inside and outside the pulse. This can be at a modest level, as for backscattering, or extreme as in the case of forwardscattering when the Raman scattered light can be trapped within the laser pulse. The consequent feedback between modes within the pulse allows solutions, absolutely growing in the pulse frame, to be found.

scholarly journals Broadband THz Sources from Gases to Liquids

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Yiwen E ◽  
Liangliang Zhang ◽  
Anton Tcypkin ◽  
Sergey Kozlov ◽  
Cunlin Zhang ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Laser Pulses ◽  
High Energy ◽  
Wave Generation ◽  
High Energy Density ◽  
Intense Laser ◽  
Thz Radiation ◽  
Flowing Liquid ◽  
Thz Wave ◽  
Thz Sources

Matters are generally classified within four states: solid, liquid, gas, and plasma. Three of the four states of matter (solid, gas, and plasma) have been used for THz wave generation with short laser pulse excitation for decades, including the recent vigorous development of THz photonics in gases (air plasma). However, the demonstration of THz generation from liquids was conspicuously absent. It is well known that water, the most common liquid, is a strong absorber in the far infrared range. Therefore, liquid water has historically been sworn off as a source for THz radiation. Recently, broadband THz wave generation from a flowing liquid target has been experimentally demonstrated through laser-induced microplasma. The liquid target as the THz source presents unique properties. Specifically, liquids have the comparable material density to that of solids, meaning that laser pulses over a certain area will interact with three orders more molecules than an equivalent cross-section of gases. In contrast with solid targets, the fluidity of liquid allows every laser pulse to interact with a fresh area on the target, meaning that material damage or degradation is not an issue with the high-repetition rate intense laser pulses. These make liquids very promising candidates for the investigation of high-energy-density plasma, as well as the possibility of being the next generation of THz sources.

scholarly journals Diagnosis of peak laser intensity from high-energy ion measurements during intense laser interactions with underdense plasmas

2000 ◽  
Vol 18 (4) ◽  
pp. 595-600 ◽  
Author(s):  
K. KRUSHELNICK ◽  
E. CLARK ◽  
Z. NAJMUDIN ◽  
M. SALVATI ◽  
M.I.K. SANTALA ◽  
...  
Keyword(s):  
Laser Pulses ◽  
High Energy ◽  
Intense Laser ◽  
Power Laser ◽  
Laser Propagation ◽  
Spatially Resolved ◽  
Ion Energies ◽  
Underdense Plasmas ◽  
Ion Emission ◽  
Helium Neon

Experiments were performed using high-power laser pulses (greater than 50 TW) focused into underdense helium, neon, or deuterium plasmas (ne ≤ 5 × 1019 cm−3). Ions having energies greater than 300 keV were measured to be produced primarily at 90° to the axis of laser propagation. Ion energies greater than 6 MeV were recorded from interactions with neon. Spatially resolved pinhole images of the ion emission were also obtained and were used to estimate the intensity of the focused radiation in the interaction region.

Self-organization and control in stimulated Raman backscattering

2013 ◽  
Vol 79 (6) ◽  
pp. 1003-1006 ◽  
Author(s):  
MILOŠ M. ŠKORIĆ ◽  
LJUBOMIR NIKOLIĆ ◽  
SEIJI ISHIGURO
Keyword(s):  
High Energy Physics ◽  
Stimulated Raman Scattering ◽  
High Sensitivity ◽  
Electron Plasma ◽  
High Energy ◽  
Pulse Generation ◽  
Laser Fusion ◽  
Nonlinear Frequency ◽  
Absorption Length ◽  
Stimulated Raman

AbstractA stimulated Raman scattering (SRS) on electron plasma waves in underdense plasmas is of a big concern in laser fusion due to an energy loss and target preheating. Complex features of large Backward-SRS (BRS) in experiments and simulations with laser fusion targets are found. Recently, to reach ultra-high intensities at multi-exawatts and beyond, relevant to high-energy physics, Raman amplification based on BRS was proposed; still, with high sensitivity and a narrow operational window. Firstly, we revisit a standard three-coupled mode model of BRS to show that the condition for an absolute instability is readily satisfied in uniform plasmas which excites large Raman signals from a background noise. It sets in for interaction length L0 shorter than, both, the plasma length L and absorption length La. Further, we point out a generic BRS feature, which due to a nonlinear frequency shift in large electron plasma wave (relativistic/trapping effects), instead to a steady state, saturates via intermittent pulsations with incoherent spectral broadening. A ‘break up’ of Manley–Rowe invariants is shown to predict non-stationary BRS. Finally, an intermediate intensity regime is originally proposed for coherent femto-second pulse generation in a thin exploding foil plasma, with scalings investigated by theory and particle simulations.

scholarly journals Ultra-intense laser pulses in near-critical underdense plasmas – radiation reaction and energy partitioning

2017 ◽  
Vol 83 (2) ◽  
Author(s):  
Erik Wallin ◽  
Arkady Gonoskov ◽  
Christopher Harvey ◽  
Olle Lundh ◽  
Mattias Marklund
Keyword(s):  
Laser Pulse ◽  
Pulse Propagation ◽  
Laser Energy ◽  
Radiation Reaction ◽  
Laser Pulses ◽  
High Energy ◽  
Intense Laser ◽  
Long Distance ◽  
Weakly Nonlinear ◽  
Highly Nonlinear

Although, for current laser pulse energies, the weakly nonlinear regime of laser wakefield acceleration is known to be the optimal for reaching the highest possible electron energies, the capabilities of upcoming large laser systems will provide the possibility of running highly nonlinear regimes of laser pulse propagation in underdense or near-critical plasmas. Using an extended particle-in-cell (PIC) model that takes into account all the relevant physics, we show that such regimes can be implemented with external guiding for a relatively long distance of propagation and allow for the stable transformation of laser energy into other types of energy, including the kinetic energy of a large number of high energy electrons and their incoherent emission of photons. This is despite the fact that the high intensity of the laser pulse triggers a number of new mechanisms of energy depletion, which we investigate systematically.

Sign in / Sign up

Export Citation Format

Share Document