Sergey Pikuz | Searcharxiv

arXiv2026

Monte Carlo Simulations of Suprathermal Enhancement in Advanced Nuclear Fusion Fuels

Suprathermal fusion reactions, initiated by energetic particles slowing down and scattering in dense plasmas, can modify the burn dynamics at inertial confinement fusion (ICF) regimes. A 0D time-dependent Monte-Carlo code has been developed to assess the suprathermal energy gain from fast fusions in DT, deuterium, $^{11}$BH$_3$ and $^{11}$BHDT fuels. It incorporates modified Li-Petrasso stopping powers, thermal broadening of cross-sections, anisotropic nuclear elastic and neutron elastic scattering, and a physical model for the p$^{11}$B alpha-particle spectra. Results show that earlier predictions of suprathermal criticality in pure deuterium are overestimated by more than an order of magnitude; no realistic density-temperature regime supports a self-sustaining chain reaction. Only DT demonstrates a critical regime provided there is no neutron leakage. Fast protons in $^{11}$BH$_3$ have an optimum energy of 4 MeV for maximising suprathermal enhancement. In this case the additional energy from fast fusions is unlikely to exceed 40% of the initial proton beam energy. The possibility of an alpha-particle-driven "avalanche" mechanism is ruled out since the ionic stopping is dominated by collisions involving small energy transfer. Suprathermal multiplication processes are dominated by neutron-driven ion up-scattering and likely play a limited role in purely aneutronic fuels.

physics.plasm-ph↗

arXiv2018

Young Stars and their Variability with LSST

Young stars exhibit short-term photometric variability caused by mass accretion events from circumstellar disks, the presence of dusty warps within the inner disks, starspots that rotate across the stellar surfaces, and flares. Long-term variability also occurs owing to starspot longevity and cycles, and from changes in stellar angular momenta and activity as the stars age. We propose to observe the Carina star-forming region in different bands with a cadence of 30 minutes every night for one week per year to clarify the nature of both the short-term and long-term variability of the thousands of young stars in this region. By obtaining well-sampled multicolor lightcurves of this dense young cluster, LSST would acquire the first statistically significant data on how these objects vary on both short and long timescales. This information will allow us to relate the observed variability to stellar properties such as mass, age, binarity, and to environmental properties such as location within or exterior to the H II region, and to the presence or absence of a circumstellar disk.

astro-ph.SR↗