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Lasers for Thermonuclear Fusion
Published in Hitendra K. Malik, Laser-Matter Interaction for Radiation and Energy, 2021
Researchers have proved that the high-power lasers of pulse lengths >1 ns play a key role in the study of high-energy density physics. There are numerous important applications in the field of ICF and astrophysics. Plasma physics covers a variety of topics, namely parametric instability, inverse Bremsstrahlung absorption, wave breaking, and so forth. In the early 1970s, physicists tried to find the answer to a fundamental question about electron heating by intense laser light. Scientists extensively studied hot electron generation in the resonance absorption condition in the 1980s. This was done considering the relation with hot electron transport. At the NIF, various challenges have been answered for the interactions of plasma with long-pulse high-energy lasers by considering the nominal hohlraum target for achieving ignition. The research related to parametric instability suppression has been performed with a broadband and random phase laser beam in the last few decades. Recently, focus is oriented on stimulated Raman scattering (SRS) and the associated generation of high-energy electrons in reactor-sized plasma, the coupling of hydrodynamic instability with filamentation instability, and so forth. The physics of plasmas and laser plasma interactions attract many physicists to work towards the indirect drive fusion scheme.
Plasma Nanotechnology for Nanophase Magnetic Material Synthesis
Published in Sam Zhang, Dongliang Zhao, Advances in Magnetic Materials, 2017
Rajdeep Singh Rawat, Ying Wang
High-energy-density plasmas, by definition, refer to plasmas that are heated and compressed to extreme energy densities, exceeding 1011 J/m3 (the energy density of a hydrogen molecule) [11]. The magnitude of plasma and other physical parameters associated with high-energy-density physics is enormous: shockwaves at hundreds of km/s (approaching a million kilometers per hour), temperatures of millions of degrees, and pressures that exceed 100 million atmospheres. Plasmas with energy densities in the range of 1–10 × 1010 J/m3 are also now classified as high-energy-density plasmas. The DPF device is referred to as high-energy-density plasma facility as the energy density of pinch plasma in DPF devices, estimated by dividing the energy stored in the DPF capacitor bank by the volume of the final pinch plasma column, is reported to be in the range of 1.2–9.5 × 1010 J/m3 [12]. Figure 4.1 shows the clear differences, in terms of plasma parameters, between routinely used low-temperature plasmas in plasma nanotechnology and high-energy-density DPF device plasmas, which are emerging as novel plasma nanotechnology tools with both plasma densities and temperatures to be about a minimum of two to three orders of magnitude higher than that of low-temperature plasmas. It is not only the plasma temperature and the plasma density that are different in DPF devices compared to low-temperatures plasma devices but there are also several other features that uniquely belong to DPF devices, which will be discussed later.
Selected High-Energy Photon Applications
Published in Harry E. Martz, Clint M. Logan, Daniel J. Schneberk, Peter J. Shull, X-Ray Imaging, 2016
Harry E. Martz, Clint M. Logan, Daniel J. Schneberk, Peter J. Shull
Inertial confinement fusion (ICF) and high-energy density physics (HEDP) research is being conducted at large laser facilities, such as the University of Rochester's Laboratory for Laser Energetics OMEGA facility and the LLNL'S National Ignition Facility (NIF). At such facilities, millimeter-sized targets with micrometer structures are studied in a variety of hydrodynamic, radiation transport, equation-of-state, ICF, and high-energy density experiments. The extreme temperatures and pressures achieved in these experiments make the results susceptible to imperfections in the fabricated targets (Lindl 1998; Haan et al. 2004). Targets include materials varying widely in composition (~3 < Z < ~82), density (~0.03 to ~20 g/cm3), geometry (planar to spherical), and embedded structures (joints to subassemblies). Fabricating these targets with structures to the tolerances required is a challenging engineering problem that the ICF (Sater et al. 1998) and HEDP (Hibbard et al. 2004) communities are currently undertaking. NDC provides a valuable tool in material selection, component inspection, and the final pre-shot assemblies' inspection (Martz and Albrecht 2003). X-rays are a key method used for the NDC of these targets.
Target Design for XFEL Experiments
Published in Fusion Science and Technology, 2023
A. Strickland, P. Hakel, N. M. Hoffman, S. H. Batha
A future phase of this experiment is to use the short-pulse laser to create a large number of “hot” electrons (a population of ≈100-keV electrons) that mimic those produced by laser-plasma instabilities. It is hypothesized that the presence of this nonthermal population of electrons will move the plasma into a non-local thermodynamic equilibrium (non-LTE) state. Laser-produced plasmas are often out of local thermal equilibrium (LTE) on account of the electron-driven collisional atomic rates being too slow to establish LTE.[18] The departure from LTE can also appear when the electron distribution is non-Maxwellian, i.e., when the free electrons are not in equilibrium even among themselves.[19] Experiments would compare emitted X-ray spectra from the plasma with and without the hot electrons to establish whether the hot electrons can alter the atomic states of the atoms. This result is important for understanding supernova evolution[20,21] and for determining the radiation drive in high-energy-density physics experiments such as radiation transport.
Radiation Protection at Petawatt Laser-Driven Accelerator Facilities: The ELI Beamlines Case
Published in Nuclear Science and Engineering, 2023
Anna Cimmino, Veronika Olšovcová, Roberto Versaci, Dávid Horváth, Benoit Lefebvre, Andrea Tsinganis, Vojtěch Stránský, Roman Truneček, Zuzana Trunečková
The Allegra Laser For Acceleration (ALFA) experimental station, instead, uses the L1-ALLEGRA laser to generate a 50-MeV electron beam.23 The Testbed for high Repetition-rate Sources of Accelerated particles (TERESA) is designed for proton and electron acceleration24 using the L3-HAPLS laser. Its goal is to provide proton beams of 10 to 15 MeV and electron beams of 100 to 150 MeV. The ELI Multidisciplinary Applications of laser-Ion Acceleration (ELIMAIA), instead, aims at ion acceleration using the L3-HAPLS and L4-ATON lasers; in its first phase it will accelerate protons up to 60 MeV and later up to 250 MeV (Ref. 25). Finally, the Plasma Physics Platform (P3) is a multifunctional experimental infrastructure. With its 50-m3 vacuum chamber, it pursues an ambitious experimental program in high-field laser-plasma interaction as well as high-energy density physics.26 P3 is served by the L3-HAPLS and L4-Aton laser systems and is designed to simultaneously focus up to five different laser beams.
Ne-like Ge soft X-ray lasers driven by fundamental- and double-frequency lasers
Published in Journal of Modern Optics, 2022
C. Wang, H. H. An, X. M. Qiao, Z. H. Fang, J. Xiong, Z. Y. Xie, Z. Y. He, E. F. Guo, Z. D. Cao, J. R. Sun, W. D. Zheng, R. R. Wang, A. L. Lei, W. Wang
As a probe, soft X-ray lasers constitute a simple and effective method to diagnose high-temperature dense plasma [1–3]. Such lasers constitute valuable tools in experimental high-energy density physics, inertial confinement fusion, laboratory astrophysics, and other related fields [4–7]. Compared to harder X-rays at the keV level [8], or visible and ultraviolet lasers [9] that are commonly used as probes, soft X-ray lasers have significantly interesting characteristics. One such characteristic is the moderate wavelength between keV X-rays and visible light, which is suitable for the diagnosis of plasma near the critical surface of a laser as a result of the appropriate level of penetration. An additional benefit of mature multilayer soft X-ray optical element technology [10] is that it is easy to obtain a high spatial resolution with low aberration imaging. At the same time, the good coherence of soft X-ray lasers allows for the direct use of the interferometer method [2,3]. Because of these characteristics, there exist widespread applications for soft X-ray laser probes to diagnose high-temperature dense plasma.