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We have investigated space and astrophysical phenomena in nonrelativistic laboratory plasmas with long high-power lasers, such as collisionless shocks and magnetic reconnections, and have been exploring relativistic regimes with intense short pulse lasers, such as energetic ion acceleration using large-area suspended graphene. Increasing the intensity and repetition rate of the intense lasers, we have to handle large amounts of data from the experiments as well as the control parameters of laser beamlines. Artificial intelligence (AI) such as machine learning and neural networks may play essential roles in optimizing the laser and target conditions for efficient laser ion acceleration. Implementing AI into the laser system in mind, as the first step, we are introducing machine learning in ion etch pit analyses detected on plastic nuclear track detectors. Convolutional neural networks allow us to analyze big ion etch pit data with high precision and recall. We introduce one of the applications of laser-driven ion beams using AI to reconstruct vector electric and magnetic fields in laser-produced turbulent plasmas in three dimensions. [ABSTRACT FROM AUTHOR]

A relativistic laser pulse, confined in a cylindrical-like target, under specific conditions may perform multiple scattering along the internal target surface. This results in the confinement of the laser light, leading to a very efficient interaction. The demonstrated propagation of the laser pulse along the curved surface is just yet another example of the “whispering gallery” effect, although nonideal due to laser-plasma coupling. In the relativistic domain its important feature is a gradual intensity decrease, leading to changes in the interaction conditions. The process may pronounce itself in plenty of physical phenomena, including very efficient electron acceleration and generation of relativistic magnetized plasma structures. [ABSTRACT FROM AUTHOR]

We present the general challenges of plasma diagnostics for laser-produced plasmas and give a few more detailed examples: spherically bent crystals for X-ray imaging, velocity interferometers (VISAR) for shock studies, and proton radiography. [ABSTRACT FROM AUTHOR]

Abstract: In the fast ignition approach to inertial confinement fusion (ICF), the ignition is expected to be triggered by an ultra-high intensity laser-produced fast electron beam, propagating and releasing its energy at the core of the shock-compressed deuterium–tritium (DT) capsule. Therefore the study of fast electron generation and transport is crucial for fast ignition science. As a consequence of fast electron transport, K-shell ionization of the medium atoms is produced with the subsequent emission of a K-alpha photon. The imaging of K-α sources is therefore very useful to obtain both quantitative and qualitative information on fast electron transport. Spherically bent crystals can provide 2-D spatially resolved and mono-energetic images of the K-α source and are widely used in several fast ignition oriented experiments. [ABSTRACT FROM AUTHOR]

A variety of targets with different dimensions and materials was irradiated using the VULCAN PW laser [C. N. Danson et al., Nucl. Fusion 44, S239 (2004)]. Using transverse optical shadowgraphy in conjunction with a one-dimensional radiation hydrodynamics code it was possible to determine a longitudinal temperature gradient. It was demonstrated for thick targets with a low Z substrate and a thin higher Z tracer layer at the rear that the boundary between the two materials was Rayleigh–Taylor unstable. By including a simple bubble growth model into the calculations it was possible to correct for the associated behavior with regard to temperature. The resulting temperature gradient was in good agreement with the previously published data using two different methods of determining the temperature. [ABSTRACT FROM AUTHOR]

A variety of targets with different dimensions and materials was irradiated using the VULCAN PW laser [C. N. Danson et al., Nucl. Fusion 44, S239 (2004)]. Using transverse optical shadowgraphy in conjunction with a one-dimensional radiation hydrodynamics code it was possible to determine a longitudinal temperature gradient. It was demonstrated for thick targets with a low Z substrate and a thin higher Z tracer layer at the rear that the boundary between the two materials was Rayleigh–Taylor unstable. By including a simple bubble growth model into the calculations it was possible to correct for the associated behavior with regard to temperature. The resulting temperature gradient was in good agreement with the previously published data using two different methods of determining the temperature. [ABSTRACT FROM AUTHOR]