The presence of a preformed ion channel in a laser accelerator enhances the oscillatory velocity of electrons due to the confined motions that leads to increase the energy gain from acceleration. The unique properties of radially polarized laser beam are utilized which leads to improvement in trapping and acceleration of electron so that an electron can be accelerated further to a very high energy level. The enhancement in electron energy is due to fact that the radial field vanishes on axis, but only axial field survives which accelerates the electron longitudinally. The electrostatic field generated by an ion channel stops the electrons to escape from the interaction region due to the transverse oscillations and thus causes a resonance between the electrons and the electric field of laser pulse. Our results show that the combined role of radial polarization and the effect of an ion channel can enhance the electron energy gain significantly.

Electron Acceleration by a Radially Polarized Laser Pulse in an Ion Channel

A coil-capacitor target is modeled using FEM simulations and analytical calculations, which allow to explain the time evolution of such complex target during magnetic field production driven by the flow of an extremely high current generated through the interaction with a high power laser. The numerical model includes a detailed study of the magnetic field produced by the coil-capacitor target, both in the static and transient cases, as well as magnetic force and Joule heating. The model is validated by experimental data reported in literature and can be of interest for several applications. As an example, the combination of two synchronized nanosecond lasers with the purpose of producing a plasma responsible of the proton-boron (p+ + 11B → 8.5 MeV + 3α) fusion reaction, and energizing two multi-turn coils with the main purpose of confining such a plasma could enhance the reaction rate. The preliminary conceptual design of a magnetic mirror configuration to be used for confining protons and boron ions up ...

Numerical simulations to model laser-driven coil-capacitor targets for generation of kilo-Tesla magnetic fields

On the design of a robust kiloTesla spiral magnet

Fusion energy from reacting hydrogen (protons) with the boron isotope 11 (HB11) resulting in three stable helium nuclei, is without problem of nuclear radiation in contrast to DT fusion. But the HB11 reaction driven by nanosecond laser pulses with thermal compression and ignition by lasers is extremely difficult. This changed radically when irradiation with picosecond laser pulses produces a non-thermal plasma block ignition with ultrahigh acceleration. This uses the nonlinear (ponderomotive) force to surprisingly resulting in same thresholds as DT fusion even under pessimistic assumption of binary reactions. After evaluation of reactions trapped cylindrically by kilotesla magnetic fields and using the measured highly increased HB11 fusion gains for the proof of an avalanche of the three alphas in secondary reactions, possibilities for an absolutely clean energy source at competitive costs were concluded.

S. Moustizis

Papers

Picosecond-petawatt laser-block ignition of avalanche boron fusion by ultrahigh acceleration and ultrahigh magnetic fields