Fundamental Architecture and Analysis of an Antimatter Ultra-Intense Laser Derived Pulsed Space Propulsion System

Antimatter has been generated in large quantities by the Lawrence Livermore National Laboratory Titan laser. The Titan laser is an ultra-intense laser system on the order of approximately 1020W/cm2 with pulse durations of roughly 1ps. With the Titan laser incident on a high atomic number target, such as gold, antimatter on the scale of 2 × 1010 positrons are generated. Roughly 90% of the generated positrons are ejected anisotropic and aft to the respective target. The mechanisms for the laser-derived positron antimatter generation involve electron interaction with the nuclei based on bremsstrahlung photons that yield electron-positron pairs as a consequence of the Bethe-Heitler process, which predominates the Trident process. Given the constraints of the current and near future technology space, a pulsed space propulsion configuration is advocated for antimatter derived space propulsion, similar in concept to pulsed radioisotope propulsion. Antimatter is generated through an ultra-intense laser on the scale of a Titan laser incident on a gold target and annihilated in a closed chamber, representative of a combustion chamber. Upon reaching a temperature threshold, the closed chamber opens, producing a pulse of thrust. The implication of the pulsed space propulsion antimatter architecture is that the energy source for the antimatter propulsion system can be decoupled from the actual spacecraft. In contrast to conventional chemical propulsion systems, which require storage of its respective propulsive chemical potential energy, the proposed antimatter propulsion architecture may have the energy source at a disparate location from the spacecraft. The ultra-intense laser could convey its laser energy over a distance to the actual spacecraft equipped with the positron antimatter pulsed space propulsion system. Hydrogen is considered as the propulsive fluid, in light of its low molecular weight. Fundamental analysis is applied to preliminarily define the performance of the positron antimatter derived pulsed space propulsion system. The fundamental performance analysis of the antimatter pulsed space propulsion system successfully reveals the architecture is viable for further evaluation.

Advanced Concept Ramjet Propulsion System Utilizing In-Situ Positron Antimatter Derived from Ultra-Intense Laser with Fundamental Performance Analysis

The fundamental performance analysis of an advanced concept ramjet propulsion system using antimatter is presented. Antimatter is generated by ultra-intense laser pulses incident on a gold target. The scientific foundation for the generation of antimatter by an ultra-intense laser was established in the early 1970’s and later demonstrated at Lawrence Livermore National Laboratory from 2008 to 2009. Antimatter on the scale of 2 × 1010 positrons were generated through a ~1 ps pulse from the Lawrence Livermore National Laboratory Titan laser that has an intensity of ~1020 W/cm2. The predominant mechanism is the Bethe-Heitler process, which involves high-energy bremsstrahlung photons as a result of electron-nuclei interaction. Propulsion involving lasers through chemical rather than non-chemical interaction has been previously advocated by Phipps. The major utilities of the ultra-intense laser derived antimatter ramjet are the capability to generate antimatter without a complex storage system and the ability to decouple the antimatter ramjet propulsion system from the energy source. For instance the ultra-intense laser and energy source could be terrestrial, while the ramjet could be mounted to a UAV as a propulsion system. With the extrapolation of current technologies, a sufficient number of pulses by ultra-intense lasers are eventually anticipated for the generation of antimatter to heat the propulsive flow of a ramjet. Fundamental performance analysis is provided based on an ideal ramjet derivation that is modified to address the proposed antimatter ramjet architecture.

Fundamental Architecture and Performance Analysis of Photofission Pulsed Space Propulsion System Using Ultra-Intense Laser

Photofission enables a unique capability for the domain of non-chemical space propulsion. An ultra-intense laser enables the capacity to induce nuclear fission through the development of bre- msstrahlung photons. A fundamental architecture and performance analysis of a photofission pulsed space propulsion system through the operation of an ultra-intense laser is presented. A historical perspective of previous conceptual nuclear fission propulsion systems is addressed. These applications use neutron derived nuclear fission;however, there is inherent complexity that has precluded further development. The background of photofission is detailed. The conceptual architecture of photofission pulsed space propulsion and fundamental performance parameters are established. The implications are the energy source and ultra-intense laser can be situated far remote from the propulsion system. Advances in supporting laser technologies are anticipated to increase the potential for photofission pulsed space propulsion. The fundamental performance analysis of the photofission pulsed space propulsion system indicates the architecture is feasible for further evaluation.

Project New Orion: Pulsed Nuclear Space Propulsion Using Photofission Activated by Ultra-Intense Laser

Project New Orion entails a pulsed nuclear space propulsion system that utilizes photofission through the implementation of an ultra-intense laser. The historical origins derive from the endeavors of Project Orion, which utilized thermonuclear devices to impart a considerable velocity increment on the respective spacecraft. The shear magnitude of Project Orion significantly detracts from the likelihood of progressive research development testing and evaluation. Project New Orion incorporates a more feasible pathway for the progressive research development testing and evaluation of the pulsed nuclear space propulsion system. Photofission through the application of an ultra-intense laser enables a much more controllable and scalable nuclear yield. The energy source for the ultra-intense laser is derived from a first stage liquid hydrogen and liquid oxygen chemical propulsion system. A portion of the thermal/kinetic energy of the rocket propulsive fluid is converted to electrical energy through a magneto-hydrodynamic generator with cryogenic propellant densification for facilitating the integral superconducting magnets. Fundamental analysis of Project New Orion demonstrates the capacity to impart a meaningful velocity increment through ultra-intense laser derived photofission on a small spacecraft.

Numerical studies on pair production in ultra-intense laser interaction with a thin solid-foil

A theoretical and numerical model of photon and electron–positron pair production in strong-field quantum electrodynamics（QED） is described. Two processes are contained in our QED theoretical model, one is photon emission in the interaction of ultra-intense laser with relativistic electron（or positron）, and the other is pair production by a gamma-ray photon interacting with the laser field.This model has been included in a PIC/MCC simulation code named BUMBLEBEE 1 D, which is used to simulate the laser plasma interaction. Using this code, the evolutions of electron–positron pair and gamma-ray photon production in ultra-intense laser interaction with aluminum foil target are simulated and analyzed. The simulation results revealed that more positrons are moved in the opposite direction to the incident direction of the laser under the charge separation field.

Self-Thomson Backscattering of Ultra-Intense Laser from Thin Foil Target

An electromagnetic solitary structure in attosecond regime is identified, costreaming with electron bunch. It is observed via nonlinear process of Self-Thomson backscattering of an ultra-intense laser from thin foil target. The process is termed as Self-Thomson Backscattering since the counter propagating electron sheets are generated by the drive laser itself. The radiation pressure acceleration model is considered for the interaction of a super-intense linearly polarized laser pulse with a thin foil in one-dimensional (1D) particle-in-cell (PIC) simulations.

Positron Induced Fusion Pulsed Space Propulsion through an Ultra-Intense Laser

A pulsed space propulsion system using position antimatter to induce Deuterium-Tritium fusion through an ultra-intense laser incident on a gold target is conceptually presented through fundamental performance analysis. As opposed to traditional strategies positron antimatter is considered rather than antiproton antimatter. Positron antimatter can be produced by an ultra- intense laser incident on a high atomic number target, such as gold. The ultra-intense laser production of positron antimatter mechanism greatly alleviates constraints, such as requirements for antimatter storage imperative for antiproton antimatter. Also the ultra-intense laser and associated energy source can be stationary or positioned remote while the pulsed space propulsion system using position antimatter to induce Deuterium-Tritium fusion is in flight. Various mechanisms for antimatter catalyzed fusion are considered, for which the preferred mechanism is the antiproton hotspot ignition strategy. Fundamental performance analysis is subsequently applied to derive positron antimatter generation requirements and associated propulsion performance. The characteristics of the pulsed space propulsion system using position antimatter to induce Deuterium-Tritium fusion through an ultra-intense laser incident on a gold target imply a promising non-chemical propulsion alternative for the transport of bulk cargo to support space missions.

Controlled Fusion Strategy Using Ultra-Intense Laser Derived Positron Generation for Initiation

A controllable strategy for eliciting nuclear fusion is presented through ultra-intenselaser derived positron generation by a conceptual first physics perspective. The capability to generate positrons on demand in a controlled manner through an ultra-intense laser incident on a high atomic number target, such as gold, is the intrinsic core to the foundation of controllable nuclear fusion. Positron antimatter generated from the periphery of the fusion fuel pellet provides the basis for initiating the fusion reaction, which is regulated by controlling the operation of the ultra-intense laser. A dual pulsed Fast Ignition mechanism is selected to achieve the fusion reaction. Based on first physics performance analysis the controllable strategy for eliciting nuclear fusion through ultra-intenselaser derived positron generation offers a realizable means for achieving regulated nuclear fusion. A future perspective of the controllable fusion strategy addresses the opportunities and concerns of a pathway toward regulated nuclear fusion.

Imaging plate scanners calibration and the attenuation behavior of imaging plate signals

Based on previously reported work, we propose a new method for calibrating image plate(IP) scanners, offering greater flexibility and convenience, which can be extended to the calibration tasks of various scanner models. This method was applied to calibrate the sensitivity of a GE Typhoon FLA 7000 scanner. Additionally, we performed a calibration of the spontaneous signal attenuation behavior for BAS-MS, BAS-SR, and BAS-TR type IPs under the 20±1℃ environmental conditions, and observed significant signal carrier diffusion behavior in BAS-MS IP. The calibration results lay a foundation for further research on the interaction between ultra-short, ultra-intense lasers and matter.

Insulator-metal transition in CaTiO3 quantum dots induced by ultrafast laser pulses

According to time-dependent density functional theory(TDDFT),we study the interactions between ultra-fast laser pulses and two kinds of calcium titanate quantum dots(PCTO-QDs and MCTO-QDs).Under the action of localized field effect,ultrafast laser can induce quantum dots to make the transition from insulator to metal.The PCTO-QDs are ultimately metallic,while the MCTO-QDs are still insulator after experiencing metal state.This is bacause the stability of the unsaturated atoms in the outermost layer of PCTO-QDs is weak and the geometric configuration of MCTO-QDs as a potential well will also reduce the damage of laser.Moreover,laser waveforms approaching to the intrinsic frequency of quantum dots tend to cause the highest electron levels to cross the Fermi surface.In this paper,it is reported that the insulating quantum dots can be transformed into metal by adjusting the intensity and frequency of laser.The importance of local morphology is emphasized by comparing two kinds of CTO-QDs.More importantly,it is an important step to identify the potential properties of perovskite materials.

Generation mechanism of 100 MG magnetic fields in the interaction of ultra-intense laser pulse with nanostructured target

Experimental and simulation data[Moreau et al.,Plasma Phys.Control.Fusion 62,014013(2019);Kaymak et al.,Phys.Rev.Lett.117,035004(2016)]indicate that self-generated magnetic fields play an important role in enhancing the flux and energy of relativistic electrons accelerated by ultra-intense laser pulse irradiation with nanostructured arrays.A fully relativistic analytical model for the generation of the magnetic field based on electron magneto-hydrodynamic description is presented here.The analytical model shows that this self-generated magnetic field originates in the nonparallel density gradient and fast electron current at the interfaces of a nanolayered target.A general formula for the self-generated magnetic field is found,which closely agrees with the simulation scaling over the relevant intensity range.The result is beneficial to the experimental designs for the interaction of the laser pulse with the nanostructured arrays to improve laser-to-electron energy coupling and the quality of forward hot electrons.

Characterization and application of plasma mirror for ultra-intense femtosecond lasers

The femtosecond laser pulses reflected from the self-induced plasma mirror（PM） surface are characterized. More than two orders of magnitude improvement on intensity contrast both in nanosecond and picosecond temporal scales are measured. The far-field distribution, i.e., focusability, is measured to degrade in comparison with that without using a PM. Experiments on proton accelerations are performed to test the effect of the balance between degraded focusability and increased reflectivity. Our results show that PM is an effective and robust device to improve laser contrast for applications.

MTW-OPAL:a technology development platform for ultra-intense optical parametric chirped-pulse amplification systems

Optical parametric chirped-pulse amplification implemented using multikilojoule Nd:glass pump lasers is a promising approach for producing ultra-intense pulses(>10^(23)W/cm^(2)).We report on the MTW-OPAL Laser System,an optical parametric amplifier line(OPAL)pumped by the Nd:doped portion of the multi-terawatt(MTW)laser.This midscale prototype was designed to produce 0.5-PW pulses with technologies scalable to tens of petawatts.Technology choices made for MTW-OPAL were guided by the longer-term goal of two full-scale OPALs pumped by the OMEGA EP to produce 2×25-PW beams that would be co-located with kilojoule-nanosecond ultraviolet beams.Several MTWOPAL campaigns that have been completed since“first light”in March 2020 show that the laser design is fundamentally sound,and optimization continues as we prepare for“first-focus”campaigns later this year.

Linear and nonlinear optical response of g-C_(3)N_(4)-based quantum dots

Graphite carbon nitride(g-C_(3)N_(4))attracts wide-ranging research interest due to its extraordinary physicochemical properties and promising applications ranging from heterogeneous catalysis to fuel cells.In this work,we design different g-C_(3)N_(4)-based quantum dots(g CNQDs),carry out a systematic study of optical properties,and elucidate the shape selectivity,composite nanostructure,and outfield effect.In particular,composites of g CNQDs and metal nanochains present excellent optical response,making it applicable to bioimaging,nano-plasma devices,and metalloenzyme in infrared light related fields.Besides,QDs which original bridging nitrogen atoms are replaced by amino(–NH_(2)),hydroxyl(–OH),and methyl(–CH_(3))functional groups respectively,have excellent spectral selectivity in the deep ultraviolet region.More interestingly,in the study of the laser interaction with materials,the g CNQDs exhibit extremely high stability and light corrosion resistance.Phase transition from insulation to metal is observed under the critical condition of about 5 e V intensity or 337 nm wavelength.All provided theoretical support for designs and applications in g-C_(3)N_(4)quantum devices.

The all-diode-pumped laser system POLARIS——an experimentalist's tool generating ultra-high contrast pulses with high energy

The development,the underlying technology and the current status of the fully diode-pumped solid-state laser system POLARIS is reviewed.Currently,the POLARIS system delivers 4 J energy,144 fs long laser pulses with an ultra-high temporal contrast of 5 × 1012 for the ASE,which is achieved using a so-called double chirped-pulse amplification scheme and cross-polarized wave generation pulse cleaning.By tightly focusing,the peak intensity exceeds 3.5 × 1020 W cm-2.These parameters predestine POLARIS as a scientific tool well suited for sophisticated experiments,as exemplified by presenting measurements of accelerated proton energies.Recently,an additional amplifier has been added to the laser chain.In the ramp-up phase,pulses from this amplifier are not yet compressed and have not yet reached the anticipated energy.Nevertheless,an output energy of 16.6 J has been achieved so far.

Spatiotemporal coupling investigations for Ti:sapphire-based multi-PW lasers

Emerging multi-PW-class lasers and their envisioned laser-plasma interaction applications in unprecedented intensity regimes set a very demanding frame for the precise understanding of the finest properties of these systems.In this work we present a synthesis of simulation studies on a series of less known or even completely disregarded spatiotemporal effects that could potentially impact greatly the performances of high-intensity lasers.

Relativistic harmonic generation by intense laser in plasmas

Starting with the nonlinear equations for describing intense laser plasma interaction,without the supposition of tenuous plasma,weak relativity and a priori assumption φ【【1+φ2,the slowly varying part and rapidly varying part of scalar potential φ,and the ratio of third harmonic to pumping laser a3/a1 in plasmas pumped by intense laser (≥1018W/cm2) are obtained.And the plasma and laser parameters favorable for generating harmonic are discussed.

Physics and applications with laser-induced relativistic shock waves

The laser-induced relativistic shock waves are described. The shock waves can be created directly by a high irradiance laser or indirectly by a laser acceleration of a foil that collides with a second static foil. A special case of interest is the creation of laser-induced fusion where the created alpha particles create a detonation wave. A novel application is suggested with the shock wave or the detonation wave to ignite a pre-compressed target. In particular, the deuterium–tritium fusion is considered. It is suggested that the collision of two laser accelerated foils might serve as a novel relativistic accelerator for bulk material collisions.

Generating monoenergetic proton beam by using circularly polarized laser

The interaction of ultrashort intense circularly polarized laser with ultra thin overdense foil is studied by particle-in-cell simulation and analytic model. It is found that with the balance between pondermotive force and electrostatic force, highly quasi-monoenergetic proton beam can be generated by Phase Stable Acceleration (PSA) process. As in conventional accelerators, ion will be accelerated and bunched up in the longitudinal direction at the same time.

Performance of an elliptical crystal spectrometer for SGⅡX-ray opacity experiments

A new crystal spectrometer for application in X-ray opacity experiments is proposed. The conditions necessary to yield broad spectral coverage with a resolution >500, strong rejection of hard X-ray backgrounds and negligible source broadening for extended sources are formulated. In addition, the design, response modeling and reporting of an elliptical crystal spectrometer in conjunction with a linear detector are presented. The measured results demonstrate the performance of the new crystal spectrometer with a broad energy coverage range, high spectral resolution, and high luminosity(good collection efficiency). This spectrometer can be used in combination with point-projection backlighting techniques as utilized in X-ray opacity experiments. Specifically, the X-ray source, transmission and self-emission spectra of the sample can be measured simultaneously in a single shot, which can reduce the experimental uncertainties from shot-to-shot fluctuations. The new crystal spectrometer has been used in the X-ray opacity experiment to precisely measure the aluminum K-absorption edge shift in the energy range around 1.560 keV in strongly compressed matter. It is demonstrated that the spectrometer can be used to realize measurements of new and unpredictable physical interactions of interest, as well as basic and applied high-energy-density science.