With the advent of high-energy-density (HED) experimental facilities, such as high-energy lasers and fast Z-pinch, pulsed-power facilities, millimeter-scale quantities of matter can be placed in extreme states of density, temperature, and/or velocity. This has enabled the emergence of a new class of experimental science, HED laboratory astrophysics, wherein the properties of matter and the processes that occur under extreme astrophysical conditions can be examined in the laboratory. Areas particularly suitable to this class of experimental astrophysics include the study of opacities relevant to stellar interiors, equations of state relevant to planetary interiors, strong shock-driven nonlinear hydrodynamics and radiative dynamics relevant to supernova explosions and subsequent evolution, protostellar jets and high Mach number flows, radiatively driven molecular clouds and nonlinear photoevaporation front dynamics, and photoionized plasmas relevant to accretion disks around compact objects such as black holes and neutron stars.

/pdf/experimental-astrophysics-with-high-power-lasers-and-z-2ws0p4rgie.pdf

Experimental astrophysics with high power lasers and Z pinches

Here is presented and discussed the history, the spectroscopic, the thermo-mechanical and the laser properties of the new old laser crystal Yb:CaF2, of its Sr and Ba isotypes as well as of an Yb and Na codoped compound. It will be shown that Yb:CaF2 is a very particular luminescent material, in which the laser-active center probably consists of a complex hexameric cluster, that it is the most promising Yb-doped fluoride material for large-scale, high-power and high-energy laser systems and that it can compete in several aspects with the currently used Yb-doped oxide crystals and glasses. The opportunity of operating the crystals at cryogenic temperatures and the recently achieved improvements in the field of femtosecond pulsed laser operation and high peak power laser amplification is highlighted and evaluated.

Yb:CaF2 — a new old laser crystal

In experiments on the parametrical amplification of femtosecond pulses in wide-aperture DKDP crystals, a power of more than 100 TW has been reached, which is much higher than the record level achieved in such lasers. The energy efficiency obtained for the parametric amplifier is equal to 27%. The energy of a 72-fs pulse is equal to 10 J.

100-TW Femtosecond Laser Based on Parametric Amplification

Three pump-3ω-probe Doppler-shift spectroscopy experiments are presented along with both 1D radiation-hydrodynamics modelling (HYADES) and 1D three-stage modelling process involving: HYADES radiation-hydrodynamics pre-pulse calculations; EPOCH kinetic particle-in-cell main-pulse calculation initialised from HYADES result; followed by hydrodynamic calculations, initialised from EPOCH result, of the evolution after the main-pulse.

These investigations are aimed at exploring the formation of shocks at the front surface of targets after interaction with an ultra-short (30 fs), ultra-intense (10^18 W/cm^2 ) laser pulse. To this end a 3ω-probe is delayed then reflected from a 3ω critical surface on the front surface to obtain a temporal profile of the velocity of this surface.

Two investigations use identical polished crown glass targets, but are performed with lasers systems with different contrast ratios (10^5 and 10^7 ). HYADES simulations match experimental results for the high contrast experiments except at early times. HYADES simulations of low contrast experiments do not agree. The three-step modelling process shows good agreement with experimental results in both cases, though with some adjustment to the pre-plasma scale-length for the low contrast case.

The third Doppler-spectroscopy experiment uses a low density (over-dense) foam target with identical setup to high-contrast case described. Experimental results show a similar magnitude Doppler-shift evolution as in low-contrast case. HYADES simulations show similarities to experimental results but not overall trend. The three-step modelling process shows that the experimental response may be due to post-soliton formation as a result of SRS or photon acceleration plasma instabilities. This is supported by an additional 2D EPOCH simulation.

A fourth theoretical investigation is presented into the transport of fast electrons produced 10^19−20 W/cm^2 laser pulses using the hybrid code ZEPHYROS. A low resistivity (< 5 µωm) at low temperatures (1 eV) is found to be of critical importance to suppressing filamentation of electron beams through low-Z targets.

Kinetic-Hydrodynamic Modelling of Short-Pulse Doppler-Shift Spectroscopy Experiments, and Resistive Filamentation of Fast-Electron Transport

High power short pulse lasers are usually based on chirped pulse amplification (CPA), where a frequency chirped
and temporarily stretched "seed" pulse is amplified by a broad-bandwidth solid state medium, which is usually
pumped by a monochromatic "pump" laser. Here, we demonstrate the feasibility of using chirped pulse Raman
amplification (CPRA) as a means of amplifying short pulses in plasma. In this scheme, a short seed pulse is
amplified by a stretched and chirped pump pulse through Raman backscattering in a plasma channel. Unlike
conventional CPA, each spectral component of the seed is amplified at different longitudinal positions determined
by the resonance of the seed, pump and plasma wave, which excites a density echelon that acts as a "chirped"
mirror and simultaneously backscatters and compresses the pump. Experimental evidence shows that it has
potential as an ultra-broad bandwidth linear amplifier which dispenses with the need for large compressor
gratings.

/pdf/chirped-pulse-raman-amplification-in-plasma-high-gain-4lf7qk5w6z.pdf

Chirped pulse Raman amplification in plasma: high gain measurements

The Vulcan Nd:glass laser at the Central Laser Facility (CLF) has recently been upgraded to the Petawatt level (1015 Watts). The three year upgrade project was contracted to deliver 500 J in a near diffraction limited pulse of 500 fs duration. The Petawatt facility will deliver an irradiance on target of 1021 W•cm-2 for a wide ranging experimental program in fundamental physics and advanced applications. This includes the interaction of super-high intensity light with matter, fast ignition fusion research, photon induced nuclear reactions, electron and ion acceleration by light waves and the exploration of the exotic world of plasma physics dominated by relativity. Of particular relevance to high speed photography, the Petawatt beam will be used to create a source for advanced high-speed imaging using protons, neutrons and X-rays on an hitherto inaccessible time-scale.

Vulcan Petawatt interaction facility

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

R. Wellstood

Author Tools

Chat about Author

Papers

Vulcan Petawatt interaction facility