Search

Summarization: This study describes the fabrication of ultrafast laser-induced periodic nanostructures on Nickel sheets and their use as cathodes in alkaline electrolysis. For the first time, to the best of our knowledge, laser-nanostructured Ni sheets were used as cathode electrodes in a custom-made electrolysis cell at actual, Hydrogen producing conditions, and their efficiency has been compared to the untreated Nickel sheets. The electrochemical evaluation showed higher Jpeaks, lower overpotential, and enhanced double-layer capacitance for the nanostructured electrode. A decrease in the Tafel slope was also found for the nanostructured electrode. The hydrogen production efficiency was found to be 3.7 times larger for the laser-nanostructured Nickel electrode, which was also confirmed by current-time measurements during electrolysis. Also, a novel approach is proposed to improve the stability of the current density during electrolysis and, therefore, the hydrogen production process by about 10%. Presented on: International Journal of Hydrogen Energy

Exceptionally high reaction gains of hydrogen protons measured with the boron isotope 11 are compared with other fusion reactions. This is leading to the conclusion that secondary avalanche reactions are happening and confirming the results of high-gain, neutron-free, clean, safe, low-cost, and long-term available energy. The essential basis is the unusual non-thermal block-ignition scheme with picosecond laser pulses of extremely high powers above the petawatt range.

Summarization: Numerical investigations on high energy proton beam interaction with high density Boron plasma allows to simulate conditions concerning the alpha production from recent experimental measurements. The experiments measure the alpha production due to p11B nuclear fusion reactions when a laser-driven high energy proton beam interacts with Boron plasma produced by laser beam interaction with solid Boron. The alpha production and consequently the efficiency of the process depends on the initial proton beam energy, proton beam density, the Boron plasma density and temperature, and their temporal evolution. The main advantage for the p11B nuclear fusion reaction is the production of three alphas with total energy of 8.9 MeV, which could enhance the alpha heating effect and improve the alpha production. This particular effect is termed in the international literature as the alpha avalanche effect. Numerical results using a multi-fluid, global particle and energy balance, code shows the alpha production efficiency as a function of the initial energy of the proton beam, the Boron plasma density, the initial Boron plasma temperature and the temporal evolution of the plasma parameters. The simulations enable us to determine the interaction conditions (proton beam-B plasma) for which the alpha heating effect becomes important. Παρουσιάστηκε στο: Research Using Extreme Light: Entering New Frontiers with Petawatt-Class Lasers III 2017

Extreme laser pulses driving non-equilibrium processes in high density plasmas permit an increase of the fusion of hydrogen with the boron isotope 11 by nine orders of magnitude of the energy gains above the classical values. This is the result of initiating the reaction by non-thermal ultrahigh acceleration of plasma blocks by the nonlinear (ponderomotive) force of the laser field, in addition to the avalanche reaction that has now been experimentally and theoretically manifested. The design of a very compact fusion power reactor is scheduled to produce then environmentally fully clean and inexhaustible generation of energy at profitably low costs. The reaction within a volume of cubic millimetres during a nanosecond can only be used for controlled power generation., 10 pages, 5 fugures

Changing the high intensity interaction time of lasers with plasma from nanosecond duration to picoseconds results in a categorically different regime. With high intensity picoseconds laser pulses, the optical energy is converted directly into kinetic energy of plasma blocks without thermal losses, without delays by collisions, and with exclusion of most of the instabilities. Following the long known theory by the nonlinear (ponderomotive) force, the plasma receives a predicted ultrahigh acceleration in agreement with measurements by Sauerbrey. Interaction of the generated plasma blocks with solid state fusion fuel should produce a side-on ignition of a Chu-Bobin fusion flame. Using hydrodynamics with separate electron and ion fluids, detailed properties can be studied about shock generation, including the varying velocity of the flame fronts far . Results from recent computations confirm how the collective nonthermal nonlinear force driven plasma interactions are causing only marginal electron heating.

One of the numerous applications of the ICAN laser using the advantage of fiber optics with chirped pulse amplification (CPA), is the scheme of side-on initiation of a nuclear fusion flame in solid density fuel with laser pulses of shorter than picosecond (ps) duration and power in the petawatt (PW) and higher range. The ICAN Fiber optics has special advantages with the potential that >900 PW spherical laser pulses may ignite the proton reaction with 11B (HB11) without the problem of dangerous radioactive radiation. Though secondary reactions can be estimated very roughly, the feasibility of a power station with the necessary energy gains can be concluded.

Fusion reactions of solid density boron-11 with protons after initiation of a fusion flame by very powerful picosecond laser pulses were derived for plane geometry. The problem of lateral energy losses with laser beams was solved by using spherical geometry, where however the gains are limited. The other elimination of losses now available by cylinder-axis symmetric 10 kilotesla magnetic fields is possible needing laser powers in the exawatt range. Estimations are presented by varying parameters for reducing the necessary laser pulse powers to lower values by up to a factor 100.

Numerical estimates for pair production from vacuum in the presence of strong electromagnetic fields are derived, for two experimental schemes : the First concerns a laser based X-FEL and the other imitates the E144 experiment. The approximation adopted in this work is that of two level multiphoton on resonance. Utilizing achievable values of laser beam parameters, an enhancedproduction efficiency of up to 10^11 and 10^15 pairs can be obtained, for the two schemes respectively., 6 pages, 4 figures

Measured highly elevated gains of proton–boron (HB11) fusion (Picciotto et al., Phys. Rev. X 4, 031030 (2014)) confirmed the exceptional avalanche reaction process (Lalousis et al., Laser Part. Beams 32, 409 (2014); Hora et al., Laser Part. Beams 33, 607 (2015)) for the combination of the non-thermal block ignition using ultrahigh intensity laser pulses of picoseconds duration. The ultrahigh acceleration above $10^{20}~\text{cm}~\text{s}^{-2}$ for plasma blocks was theoretically and numerically predicted since 1978 (Hora, Physics of Laser Driven Plasmas (Wiley, 1981), pp. 178 and 179) and measured (Sauerbrey, Phys. Plasmas 3, 4712 (1996)) in exact agreement (Hora et al., Phys. Plasmas 14, 072701 (2007)) when the dominating force was overcoming thermal processes. This is based on Maxwell’s stress tensor by the dielectric properties of plasma leading to the nonlinear (ponderomotive) force $f_{\text{NL}}$ resulting in ultra-fast expanding plasma blocks by a dielectric explosion. Combining this with measured ultrahigh magnetic fields and the avalanche process opens an option for an environmentally absolute clean and economic boron fusion power reactor. This is supported also by other experiments with very high HB11 reactions under different conditions (Labaune et al., Nature Commun. 4, 2506 (2013)).

Numerical estimates for electrons and mesons particle–antiparticle creation from vacuum in the presence of strong electromagnetic fields are derived, using the complete probability density relation of Popov’s imaginary time method (Popov, JETP Lett. 13, 185 (1971); Sov. Phys. JETP 34, 709 (1972); Sov. Phys. JETP 35, 659 (1972); Popov and Marinov, Sov. J. Nucl. Phys. 16, 449 (1973); JETP Lett. 18, 255 (1974); Sov. J. Nucl. Phys. 19, 584 (1974)); (Popov, Phys. Let. A 298, 83 (2002)), and within the framework of an experimental setup like the E144 (Burke et al., Phys. Rev. Lett. 79, 1626 (1997)). The existence of crossing point among pair creation efficiency curves of different photon energies and the role of odd/even multiphoton orders in the production rates are discussed. Finally a kind of tunability process between the two creation processes is discussed.

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., 4 pages, 3 figures, presented at IFSA 2015 conference, Seattle WA 22 SEP 2015

Summarization: Summary form only given. For the burning process of high density (about 1018cm-3) high temperature (tens of keV) plasma, the trapping by a high mirror-like magnetic field is a challenging objective. Numerical simulations1-3 may lead to conceptual designs of relatively large magnetized volumes (cm3) at large magnetic field (10 to 100T) with a tailored spatial profile. Taking the example of a Compact Magnetic Fusion (CMF) device3, 4 driven by ultra-short, high intensity laser beam interaction with cluster or solid targets, we present a pulsed power device capable of feeding a single turn coil at the level of 100s of kA and μs duration. The key component is a low inductance switch which will be described, paying attention to the triggering process, the plasma characterization, the B-field metrology and its scalability. The proposed device will be discussed in comparison with other solutions from the literature. Παρουσιάστηκε στο: Plasma Sciences , 2015 IEEE International Conference on

Nuclear fusion with confinement by available kilotesla magnetic fields allows improved performance for Inertial Confinement Fusion. The combination of this approach with the established ultrahigh laser acceleration of plasma blocks driven by nonlinear (ponderomotive) forces of ps laser pulses of exawatt power may permit high gain boron-11 fusion with protons. This potentially provides a path to very attractive fusion power stations based on aneutronic fusion.

Summarization: In experimental physics, a number of domains need the intense magnetization of a rather large volume, namely in condensed matter science. In laser-matter interaction and plasma science, the magnetic field may extend the interaction time of the charged particles. But the B-field values of interest, as predicted by analytical study or by numerical simulation, commonly overtake the 50-60T range, a limit for a reasonable capital investment. Moreover, the existing materials cannot withstand fields of 100T or more and some experiments are conducted in a semi-destructive mode, i.e. the coils explode radially, preserving the cell and the diagnostics. The single turn coil (STC) is an option for reaching such fields in a non-destructive pulsed mode. In order to study the generation of high energy particles for neutron production, we have have estimated that convenient operating conditions are a peak value of 50T in few cm3. Translated in current intensity, this objective is close to IMA with a rising time of 1 ?s. To get such a very high current, we have built a low impedance transmission line connected to a massive brass STC with a 10 to 16mm bore. Two types of capacitor banks were used, based on 4.2-?F 50-kV low-inductance Haefely caps, charged under 30kV. The key component in the flat transmission line is a surface switch which has been described previously and can have an insertion inductance as low as few nH. In this switch, a number of channels are triggered along a melamina surface by an underlying conducting comb. Under the present conditions, when the channel number is 15 or more, a significant reduction of the inductance is observed (typ. 13 to 16nH for the whole circuit) and the peak current can reach 850kA, corresponding to 26 to 30T on axis. The field mapping, recorded with a mm axial resolution, is coherent with STC calculation. The paper will describe in detail the experimental setup, the associated probes, the calibration procedure and the results.- We will conclude by presenting an alternative switch, currently under construction, able to increase the peak current, the reproducibility of B and the device lifetime. Παρουσιάστηκε στο: Pulsed Power Conference, 2009 IET European

Summarization: We present a new scheme of Ti:Sa laser amplification, based on second harmonic generation from a Ti:Sa laser tuned at 496 nm by an OPA system and amplification in an excimer double cavity. Presented on

Summarization: Ultrahigh acceleration of plasma blocks in the range of 1020 cm/s2 has been confirmed experimentally after this was long predicted as a non-thermal direct conversion of optical energy into plasma motion due to dominating nonlinear (ponderomotive) forces [1]. The use of laser pulses of more than PW power and ps or shorter duration can ignite a nuclear fusion flame in solid density deuterium tritium because the necessary energy flux of >108J/cm2 according to the theory of Chu [2] is available [3]. For the studies of the necessary velocities of the generated fusion flames above 1000 km/s the detailed processes can be analyzed by using the advanced genuine two-fluid hydrodynamic model [4] where it was surprising that the ignition of the fusion flame by the picosecond interaction needs a comparably long development in the nanosecond range before the thermal processes result in shock fronts similar to the Rakine-Hugoniot theory. For the evaluation of power generation the problem of lateral energy losses was studied by using very high pulsed magnetic fields. The recently produced 10 Kilotesla magnetic fields [5] are very promising for solutions. Παρουσιάστηκε στο: 8th International Conference on Inertial Fusion Sciences and Applications

Ignition of nuclear fusion flames in solid state density fuel following Chuʼs model of 1972 is evaluated using now available plasma blocks from ultrahigh acceleration with laser pulses of picosecond (ps) duration and power up to and beyond petawatt (PW). A new numerical approach is reported where genuine two-fluid hydrodynamics is used in order to study the shock mechanism of the generated fusion flame, its propagation velocities above 1000 km / s , and fusion efficiencies for deuterium–tritium needing an energy flux of 10 8 J / cm 2 . The results of the built-up of the shock process are reported showing a basic difference between the ps and nanosecond (ns) properties.

Summarization: The main contribution of this paper is the application of Loss Minimization control algorithm of a three-phase squirrel-cage induction motor which is used in parallel with an internal combustion engine (ICE), in hybrid electric vehicles (HEV). During steady state operation of the electric motor, the electric motor's optimal motor flux profile minimizes the electric motor losses and maximizes the overall HEV efficiency, hybridization factor (HF). During steady state operation of the direct torque controlled (DTC) induction motor, loss minimization is achieved by adjusting the magnitude of the stator flux reference as a function of the vehicle driver (pedal acceleration) and the coordinated control. The proposed stator flux optimization method initially uses a Loss Model Controller (LMC) which provides the real time fast gross approximation of the optimum motor flux and sequential uses a real time fuzzy logic search controller (FLSC). The FLSC control system, provides the real-time refinement of the motor's flux adjustment on the basis of search during the steady states. Due to the FLSC the electric motor's flux level fluctuates in steps until the measurement of electric motor's input electric power settles at a minimum. The dynamic model of the electric motor and the suggested control algorithm designed by using the MATLAB/Fuzzy Logic Toolbox®. The control algorithm is validated by numerical results by using the digital signal processor of eZdspF2812TM. Experimental results will be available upon conclusion of the laboratory testing on a 10 hp, 500 kg HEV in which an 5 hp IM is coupled in parallel with an ICE on the drive shaft of the wheels. Presented on

The application of laser pulses with psec or shorter duration enables nonthermal efficient ultrahigh acceleration of plasma blocks with homogeneous high ion energies exceeding ion current densities of $10^{12}~\text{A}~\text{cm}^{-2}$ . The effects of ultrahigh acceleration of plasma blocks with high energy proton beams are proposed for muon production in a compact magnetic fusion device. The proposed new scheme consists of an ignition fusion spark by muon catalyzed fusion ( $\unicode[STIX]{x03BC}$ CF) in a small mirror-like configuration where low temperature D–T plasma is trapped for a duration of $1~\unicode[STIX]{x03BC}\text{s}$ . This initial fusion spark produces sufficient alpha heating in order to initiate the fusion process in the main device. The use of a multi-fluid global particle and energy balance code allows us to follow the temporal evolution of the reaction rate of the fusion process in the device. Recent progress on the ICAN and IZEST projects for high efficient high power and high repetition rate laser systems allows development of the proposed device for clean energy production. With the proposed approaches, experiments on fusion nuclear reactions and $\unicode[STIX]{x03BC}$ CF process can be performed in magnetized plasmas in existing kJ $/$ PW laser facilities as the GEKKO-LFEX, the PETAL and the ORION or in the near future laser facilities as the ELI-NP Romanian pillar.