Particles

This is a comprehensive review that examines Interplanetary Coronal Mass Ejections (ICMEs) as critical drivers of energetic particle dynamics across the heliosphere, influencing both solar energetic particle (SEP) acceleration at ICME-driven shocks and the modulation of galactic cosmic rays (GCRs). The interaction of these heliospheric transients with planetary magnetospheres provides a natural laboratory for studying acceleration and transport processes in complex plasma environments. Saturn’s magnetosphere, while internally dynamic, allows partial penetration of heliospheric energetic particles into the outer and middle magnetosphere, enabling indirect solar wind diagnostics and revealing ICME-induced variations such as Forbush decreases and SEP-driven transient radiation belts. In contrast, Jupiter’s much stronger and rapidly rotating magnetosphere presents a fundamentally different regime. External solar particles—particularly SEPs—encounter significant barriers to entry due to the planet’s intense magnetic field and dense, internally sourced plasma environment, limiting direct penetration into the inner magnetosphere. Instead, Jupiter sustains high-efficiency internal acceleration processes, including wave–particle interactions and rotationally driven transport. These mechanisms energize particles to MeV and, in some cases, relativistic energies, producing radiation belts and current systems that largely mask signatures of heliospheric transients. Comparative examination of these two systems provides insight into the regulation of energetic particle acceleration, transport, and modulation in strong-field planetary environments.

The structure of the nucleon is a central problem in strong interaction physics in the non-perturbative regime. Indeed, the vast majority of the known matter in the Universe is made of protons and neutrons which are a remarkable emergent phenomenon of quantum chromodynamics. A critical aspect of investigating nucleon structure experimentally is the measurement of fundamental quantities such as the elastic nucleon form factors. Also important is the measurement of the transverse momentum dependent distribution functions. Accessing such quantities experimentally, however, is challenging because of the small cross sections involved, particularly at high momentum transfer. We present here a physics program that is addressing this challenge based on the Super Bigbite Spectrometer (SBS) that has recently been built at the Thomas Jefferson National Accelerator Facility. SBS provides a relatively large solid angle of 70 msr and can be used at high luminosities and forward-scattering angles. It is based on a single large dipole magnet in an open-geometry in which the detector package has a direct line of sight to the target. This approach is only possible through the use of detector technology that can operate at very high rates while providing excellent spatial resolution. It is the product of solid angle and luminosity that is critical when measuring small cross sections, and in this regard, among spectrometer systems at JLab, SBS is at present unique in its capability. The first set of experiments utilizing SBS has been successfully completed, and more experiments are planned for the future. We also discuss a proposed upgrade that would increase the SBS solid angle to 260 msr, thereby opening perspectives for an even broader physics program.

This research investigates crater formation during laser ablation of polymerized UDMA–TEGDMA composites, focusing on the quantitative analysis of crater volume and depth under varying laser intensities. Two types of samples were examined: composites without gold nanorods (Au0, reference sample) and composites containing resonant gold nanorod dipole antennas (Au2, plasmonic sample), with the nanorod dimensions tuned to the frequency of the incident laser irradiation. These resonant plasmonic targets were originally developed and investigated within the NAPLIFE (Nano-Plasmonic Laser Induced Fusion Energy) Collaboration, initiated in 2019. The incorporation of resonant gold nanorods enhanced the laser-induced ablation response, resulting in larger crater volumes and greater crater depths at higher laser pulse energies. In contrast, gold nanorods with non-resonant dimensions did not exhibit comparable enhancement, demonstrating that the observed effect is associated with the resonant geometry of the nanorod dipole antennas rather than simply with the presence of gold nanoparticles. Reference-line values were used to establish baseline comparisons, while the average crater depth served as a key indicator of material removal. Building on these experimental findings, the study further integrates artificial intelligence for automated crater analysis. A deep transfer learning approach using a fine-tuned ResNet-18 model was implemented to classify high-resolution crater images of Au0 and Au2 samples. By retraining the final fully connected layer while freezing the convolutional feature extractor, the model achieved a validation accuracy of 98.7 percent, demonstrating stable convergence. The results confirm that deep learning offers a powerful and reproducible framework for high-precision classification and analysis of laser-induced surface structures, paving the way for intelligent materials diagnostics and laser-process optimization.