Proton-boron fusion in a compact scheme of plasma oscillatory confinement

We present the results of experiments on the aneutronic fusion of proton-boron (pB) in a single miniature device with electrodynamic (oscillatory) plasma confinement. The device is based on a low energy $(\sim 1–2 \mathrm{J})$ nanosecond vacuum discharge with a virtual cathode, the field of which accelerates protons and boron ions to the energies required for pB synthesis $(\sim 100–300 \mathrm{keV})$ under oscillating ions' head-on collisions. The yields of $\alpha$ particles registered for different conditions of the experiment are presented and discussed in detail. The experiment was preceded by particle-in-cell modeling of main processes accompanying pB reaction within the framework of the full electromagnetic code karat. The summary yield of $\alpha$ particles of about $5\times {10}^4/4\pi$ was obtained during the pulse-periodic operation of the generator within total $4\mu \mathrm{s}$ of the high voltage applied, which is $\sim 10\alpha$ particles/ns.

Figure 1

(a) Anode (red line)-cathode (blue line) geometry in the discharge gap where the virtual cathode is formed by electrons (blue points) at 2.0 ns, and protons (red) and boron ions (yellow) are accelerating in the potential well of the virtual cathode towards the $Z$ axis where pB reaction should take place. The green area is simulated “erosion plasma” consisting of protons and boron ions. (b) Trajectories of particular groups of boron ions ($y$, $Z=+3$) and protons ($r$) during their oscillations around the axis $Z$. (c) Potential well of the virtual cathode as the possible micro-“reactor” for pB nuclear synthesis under oscillatory confinement. (d) Energy of groups of protons ($r$) and boron ions ($y$) as a function of time in the process of their oscillations in the potential well (at voltage applied $U=100$ kV). (e) Energy of all particles participating in the nuclear pB reaction as a function of their position along the radius (blue points: electrons, yellow: boron ions, red: protons, gray: ${}^8\mathrm{Be}^{*}$, purple: primary $\alpha$-particles; dark orange: products of the ${}^8\mathrm{Be}^{*}$ decay into two secondary $\alpha$-particles). (f) The yield of secondary $\alpha$-particles (a.u.) from the ${}^8\mathrm{Be}^{*}$ decay during the pB reaction in nanosecond vacuum discharge. Inset illustrates pB reaction started with the yield of products at $t=5$ ns [34].

Figure 2

(a) Sectional diagram of the discharge chamber and the arrangement of CR-39 detectors around the anode composed of Pd tubes and a hollow Al cathode with slits inside the chamber. (b) VA characteristics of the voltage pulse-periodical generator.

Figure 3

(a, b) Boron nanoparticles deposited onto the developed anode surface by cataphoresis. (c) Microrelief of the Pd anode surface.

Figure 4

Tracks on the CR-39 detector associated with $\alpha$-particles that passed through the longitudinal slits along the radius of the cathode: (a, b) for detectors O1-6 covered with $11\mu \mathrm{m}$ Al foil, (c, d) for open detectors O1-5.

Figure 5

Examples of microphotographs of the surface of the CR-39 detector: (a) for discharges with a “background” anode containing only hydrogen (there are tracks of protons only); (b) for the discharge with an anode saturated with hydrogen and covered with boron nanoparticles (tracks of protons, boron ions, and $\alpha$-particles are visible), where (c)–(f) are enlarged fragments of the images of the O1-4 detector: Panels (c, d) are open detectors, (e, f) are CR-39 covered by Al foil.

Figure 6

(a) Histogram of track areas obtained in experiments under hydrogen-filled anode with boron [Fig. 5]. (b) Similar histogram for shots with hydrogen-filled anode without boron [Fig. 5] has just a proton peak.