Abstract / Summary
Abstract Building directly upon our foundational demonstration of extreme high-pressure high-temperature (HPHT) synthesis of nanostructured tungsten-carbide/lithium-6 hydride (WC–Co/ 6 LiH) composites, this study delivers an extended experimental investigation into high-energy plasma pinch dynamics, electrode microstructural durability, and transient nuclear reaction kinetics during severe electrohydraulic shock (EHS) discharges in heavy water (D 2 O). Industrial precursor matrices (VK-6 and VK-8) consolidated under hydrostatic pressures of P = 7.6 GPa were precision-machined into composite electrodes and evaluated under sub-microsecond high-voltage breakdown. Multiphysics experimental plasma diagnostics combined with time-resolved soft X-ray continuum slope analysis confirmed a peak core electron temperature k B T e = 3.02 ± 0.25 keV ( T e ≈ 3.5 × 10 7 K) and dynamic pinch-induced shock pressures exceeding 100 GPa (> 1 Mbar). High-resolution time-of-flight (TOF) fast-neutron spectrometry revealed a prominent, thermally broadened high-energy neutron emission peak centered near ~ 14.1 MeV ( E n = 14.1 ± 0.4 MeV ) with a characteristic yield of ~ (1.2 ± 0.15) × 10 5 neutrons/pulse, matched by post-shot quadrupole mass-spectrometric detection of 4 He and 3 He gaseous ash. To address fundamental questions regarding isotopic carrier behavior, parallel experiments were conducted using composite electrodes containing pure metallic 6 Li instead of the hydride carrier ( 6 LiH). Comparative evaluation demonstrated that both configurations yield equivalent nuclear and thermal signatures within diagnostic resolution. Given the extreme transient environment of the EHS breakdown, pulse-to-pulse hydrodynamic variations exceeded any consistently resolvable difference attributable specifically to the hydride phase. A comprehensive Saha–Boltzmann continuum-lowering ionization balance model and Mie–Grüneisen equation-of-state analysis are formulated to describe the compressed discharge channel.