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The generation of energetic ions and DD neutrons from microfusion at the interelectrode space of a low-energy nanosecond vacuum discharge has been demonstrated recently [1, 2]. However, the physics of fusion processes and some results regarding the neutron yield from the database accumulated were poorly understood. The present work presents a detailed particle-in-cell (PIC) simulation of the discharge experimental conditions using a fully electrodynamic code. The dynamics of all charge particles was reconstructed in time and anode–cathode (AC) space. The principal role of a virtual cathode (VC) and the corresponding single and double potential wells formed in the interelectrode space are recognized. The calculated depth of the quasistationary potential well (PW) of the VC is about 50–60 keV, and the D+ ions being trapped by this well accelerate up to energy values needed to provide collisional DD nuclear synthesis. The correlation between the calculated potential well structures (and dynamics) and the neutron yield observed is discussed. In particular, ions in the potential well undergo high-frequency (∼80 MHz) harmonic oscillations accompanied by a corresponding regime of oscillatory neutron yield. Both experiment and PIC simulations illustrate favorable scaling of the fusion power density for the chosen IECF scheme based on nanosecond vacuum discharge.

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The energetic ions and DD neutrons from microfusion at the interelectrode space of a low energy nanosecond vacuum discharge with deuterium-loaded Pd anode has been demonstrated recently. To understand better the physics of fusion processes the detailed PIC simulation of the discharge experimental conditions have been developed using a fully electrodynamic code KARAT. The dynamics of main charge particle species was reconstructed in time and interelectrode space. The principal role of a virtual cathode (VC) and the corresponding single and double potential well formed in the interelectrode space are recognised. The calculated depth ϕ of the quasistationary potential well (PW) of the VC is about 50-60 kV, and the D + ions being trapped by this well accelerate up to energy values needed to provide collisional DD nuclear synthesis. Both experiment and PIC simulations illustrate very favourable scaling of the fusion power density at decreasing of VC radius ( ∼ ϕ 2 /r 4 V C ) for the chosen inertial electrostatic confinement fusion scheme based on miniature nanosecond vacuum discharge. Meanwhile, the initial stage of discharge is understood still poorly. When voltage is applied, the electron beam extracted from cathode starts to interact with the surface of deuterium-loaded Pd anode. This early stage of discharge manifests sometime the peaks registered by photomultipliers which are similar to neutron ones from time-of-flight measure under the study of collisional DD synthesis at the further stages of discharge. The detailed study of Pd anode surface morphology have been performed and recognized, in particular, the number of various pores and craters of different sizes. We remark that besides of rather usual craters (due to electron beams -anode interaction) some of the craters on the Pd anode surface may correspond to anode ectons (explosive centres) and consider their possible nature. Specifics of warm dense matter (WDM) generated at different stage of discharge is discussed. The data obtained are compared with recent results on initiation of DD reactions by electron beams at deuterium -loaded Pd foils and correspondent data on their surface morphology.

High frequency electrical conductivity is studied in the case of a strongly coupled quasiclassical plasma. Analytic results are derived both from the memory function formalism and the linear response theory developed earlier. The results obtained are compared with computer simulation data. Collective effects are shown to play an important rqle in optical properties of collision dominated plasmas.