Laser-Driven Proton-Only Acceleration in a Multicomponent Near-Critical-Density Plasma.

An experimental investigation of collisionless shock ion acceleration is presented using a multicomponent plasma and a high-intensity picosecond duration laser pulse. Protons are the only accelerated ions when a near-critical-density plasma is driven by a laser with a modest normalized vector potential. The results of particle-in-cell simulations imply that collisionless shock may accelerate protons alone selectively, which can be an important tool for understanding the physics of inaccessible collisionless shocks in space and astrophysical plasma.

Integrating sheath and radiation-based acceleration using scaling coefficients for tailoring radiation dominant hybrid acceleration.

An optimal target condition for generating GeV-energy ions with linearly polarized laser pulse is revealed by a hybrid acceleration theory based on the fractional contributions of the target normal sheath acceleration (TNSA) and the radiation pressure acceleration (RPA) mechanisms in the RPA-dominant regime. The theory is established with two scaling coefficients, which scale the TNSA and RPA velocities, and are sophisticated through two-dimensional particle-in-cell simulations where GeV-energy ions are obtained by RPA-dominant hybrid acceleration. By imposing limits on the scaling coefficients, three separate acceleration regions are obtained including a RPA-dominant acceleration region, which is optimal to generate GeV-energy ions.

Automation of etch pit analyses on solid-state nuclear track detectors with machine learning for laser-driven ion acceleration.

Solid-state nuclear track detectors (SSNTDs) are often used as ion detectors in laser-driven ion acceleration experiments and are considered to be the most reliable ion diagnostics since they are sensitive only to ions and measure ions one by one. However, ion pit analyses require tremendous time and effort in chemical etching, microscope scanning, and ion pit identification by eyes. From a laser-driven ion acceleration experiment, there are typically millions of microscopic images, and it is practically impossible to analyze all of them by hand.

Oral infection with Porphyromonas gingivalis augmented gingival epithelial barrier molecules alteration with aging.

Objective: Disruption of the gingival epithelial barrier is often mediated by aging or the pathogen Porphyromonas gingivalis. This study examined the combined effects of aging and P. gingivalis exposure on gingival epithelial barrier molecules.