Breakthroughs could make commercial laser nuclear fusion through billion times improvements in yield

Two recent scientific breakthroughs have opened a new way to laser fusion reactions according to startup HB11 Energy. It involves the reaction between hydrogen H and the boron isotope 11 (HB11) as uncompressed solid state fuel within an extremely high trapping magnetic field. Both of these conditions have been demonstrated by experiments and following predictions from computations.

* a 1 kilojoule laser boosts a magnetic field to 4500-10000 tesla for over one nanosecond. About 100 times stronger than powerful superconducting magnets
* a second laser causes a nuclear fusion chain reaction
* lab experiments have been performed which indicate fusion yields increase by a billion times.
* energy production with a proposed system would be four times cheaper than coal

A research paper claims experimentally confirmed reaction gains one billion times higher than the classical values, placing it far ahead any DT fusion approaches.

HB11 energy expects to be able to provide energy for about ¼ of the price of coal-fired power, without any carbon emissions or radioactive by-products, which will be disruptive to the power industry.

The specific evaluation of elastic collisions of the generated alphas with protons and boron nuclei documented how the hydrogen nuclei receive an energy within a wide range around 600 keV energy, for reacting with the 11B nuclei at nearly ten times higher fusion cross sections compared with all known other fusion reactions, to produce each three alphas etc. for the avalanche. The measurements with the nuclei for the energetic HB11 reactions on the background of less than few ten eV background plasma, could be theoretical reproduced in details. This shows the need to explore this kind of non-ideal and non-neutral plasmas. The earlier estimations of the anticipated avalanche reactions was then fully proved for use. Under simplified assumptions, the reaction of 12 mg boron fuel can produce one GJ = 277 kWh or more fusion energy, ignited in a controlled way by the one single ps irradiated laser beams in the reactor of Figure 4. The easy operation with one beam ignition should then permit a reactor with one shot per second and sufficiently fast localisation of the reaction unit using presently available technology for low cost power generation. The now presented results show an increase of the HB11 fusion gains by more than nine orders of magnitudes above the classical value.

References:
Matter and Radiation at Extremes Vol, 2 (2017) 177-189; Physics of Plasmas 23 (2016) 050704;
arXiv: 1704.07224; 1708.09722

US Patent – Method for Generating Electrical Energy by Laser-Based Nuclear Fusion and Laser Reactor US 20170125129 A1

Patent Abstract

A method for generating electrical energy, comprising the steps of providing a fusion fuel.

(1), the fusion fuel is held in a magnetic field within a cylindrical reaction chamber
(2), initiating nuclear fusion in the fusion fuel in which a fusion flame is produced by fusion laser pulses having a pulse duration of less than 10 ps and a power of more than 1 petawatt, and converting the energy that is released during the nuclear fusion from the nuclei that are produced into power plant power, wherein the magnetic field has a field strength which is greater than or equal to 1 kilotesla and the nuclear fusion has an energy yield of more than 500 per laser energy of the fusion laser pulses that produce the fusion flame.

Also described is a nuclear fusion reactor which is configured for generating electrical energy.

Arxiv – Laser boron fusion reactor with picosecond petawatt block ignition. Heinrich Hora, Shalom Eliezer, Jiaxiang Wang, Georg Korn, Noaz Nissim, Yanxia Xu, Paraskevas Lalousis, Goetz Kirchhoff, George H. Miley. 29 Jul 2017.

For developing a laser boron fusion reactor driven by picosecond laser pulses of more than 30 petawatts power, advances are reported about computations for the plasma block generation by the dielectric explosion of the interaction. Further results are about the direct drive ignition mechanism by a single laser pulse without the problems of spherical irradiation. For the sufficiently large stopping lengths of the generated alpha particles in the plasma results from other projects can be used.

Fusion of hydrogen with the boron Isotope 11, HB11 at local thermal equilibrium LTE, is 100,000 times more difficult than fusion of deuterium and tritium, DT. If – in contrast – extreme non-equilibrium plasma conditions are used with picoseconds laser pulses of more than 10PW power, the difficulties for fusion of HB11 change to the level of DT. This is based on a non-thermal transfer of laser energy into macroscopic plasma motion by nonlinear (ponderomotive) forces as theoretically predicted and experimentally confirmed as “ultrahigh acceleration”. Including elastic nuclear collisions of the alpha particles from HB11 reactions results in an avalanche process such that the energy gains from HB11 fusion is nine orders of magnitudes above the classical values. In contrast to preceding laser fusion with spherical compression of the fuel, the side-on direct drive fusion of cylindrical uncompressed solid boron fuel trapped by magnetic fields above kilotesla, permits a reactor design with only one single laser beam for ignition within a spherical reactor. It appears to be potentially possible with present day technology to build a reactor for environmentally fully clean, low-cost and lasting power generation.

Arxiv – Extreme laser pulses for possible development of boron fusion power reactors for clean and lasting energy H. Hora, S. Eliezer, G. J. Kirchhoff, G. Korn, P. Lalousis, G. H. Miley, S. Moustaizis
(Submitted on 17 Mar 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 millimeters during a nanosecond can only be used for controlled power generation.

A relatively low power laser boosts a trapping magnetic field to 4500-10000 tesla for over one nanosecond

Firing a laser beam of nanosecond duration and 1 kJ energy into the hole of the plates of Fig. 3 is triggering a current in the loops where a magnetic field of 4.5 kilotesla was measured. Most of the energy of the laser pulse in Fig. 3 goes into charging the plates which energy – apart from some losses – is converted then into magnetic field energy in the coils during one to two nanoseconds. Placing into the coil a co-axial cylinder of solid density HB11 fuel of larger radius than the radius of a second picoseconds laser pulse results in a direct drive plasma block ignition of the fuel cylinder end-on. Hydrodynamic computations showed the plasma dynamics of the magnetically trapped or confining cylinder below the second laser pulse for the magnetic field of 4.5 and of 10 kilotesla at least for one nanosecond.

All these calculations are similar to the DT fusion using binary reactions without the secondary alpha avalanche reactions. The secondary reactions of the 2.9 MeV alphas when hitting a boron nucleus and transferring about 600 MeV energy by central collision are not included in the computations. The gyro radius of the alpha particles at 10 kilotesla magnetic fields is 42.5 m and their mean free pass for collective stopping at solid state density is nearly independent on the electron temperature in the range of 60 m at solid state density but is considerably larger in plasmas according to measurements at GSI Darmstadt such that an avalanche multiplication is resulting in an exponential increase of the fusion gain until fuel depletion.

Estimations as for the cylindrical geometry of the reaction unit of Fig. 3 show how a ps-30PW laser energy input into the block for the initiation of the flame of 30 kJ can produce alpha energy of voer 1 GJ. By this way, the requested fusion gain for DT of 10000 ostulated by Nuckolls et al. for a power station are then fulfilled. The aim to produce more than 100 MJ fusion energy per pulsed fusion shot was also underlined by Feder mentioning Dawns Flicker. Her understanding with respect to the costs for a fusion power station is evident. The scheme of Nuckolls et al using relativistic electron beams for fast ignition arrives at comparable values for HB11. It is remarkable that the alpha-avalanche process is arriving at comparable values with clean HB11 fusion above those with DT.

The energy of the alpha particles can be converted by more than 97% with a minimum of thermal energy losses when being slowed down by an electric field if the reaction unit is negatively charged at nearly 1.4 megavolts (MV) against the earthed reactor wall. The energy is given by the number of alpha particles times 2.8 MV which energy can be converted into three phase ac-electricity by using the HVDC (high voltage direct current) transmission technology used for electricity power transmission over 1000 km or much higher distance with minimum of losses. If the reactor would work with one shot per second, the average dc current is 780 Amp at 1.4 MV.

The momentum of the alpha particle to the reactor wall by the alpha particles of GJ energy is reduced compared to the detonation of chemical explosives. This reduction is determined by the measures of the energetic particles. For chemical reactions the energy is up to the order of eV, while the energy of the particles of a nuclear reaction is up to the range of 10 MeV. The shock of the detonation is reduced by the square root of the ratio of the mentioned energies, i.e. in the range close to 3000 . The shock to the reactor wall is than comparable to an explosion in the range than 50g TNT, against which a over 2 meter diameter reactor wall of few cm thickness can sustain.

For an operation of up to one laser shot per second a feeding mechanism of the reaction units into the center of the reactor in vacuum at the voltage of -1.4 MeV is needed. The unit is destroyed at each shot. The hole in the reactor wall through which the unit is moved has to have a bent edge to reduce any vacuum discharge between the wall and the unit charged negative on1.4 MV together with the stick for guiding into the reactor center. The container of the feeding mechanism is on ground level like the reactor wall and has to have sufficient space for the moving stick, connected with the unit within vacuum and locks have to be provided for loading the units. This design is not trivial but well based on normal means. Lasers for the reactor for producing 30 kJ laser pulses of picosecond duration with a sequence of one shot per second are close to the present technology should be available within few years. At the moment lasers with 10 kJ pulses of 0.17 ps duration and operation of one shot per minute are available or 1 kJ pulses of the same duration at 10 Hz emission.

Avalanche result has been proven experimentally with an increase of nine orders of magnitude of alpha particle production than expected from classical consideration. Our results can be verified with existing technologies and show that our clean fusion reactor can be achieved.

The result of the boron laser fusion reactor teaches how important it is to develop the theory of high temperature plasmas beyond the main stream of the thermal equilibrium state towards the plasmas with mixed states. These are the few hundreds keV non-thermalised energetic ions performing elastic collisions and fusion reactions in this broad energy range to happen within the plasma of about solid state densities and temperatures of 10 to 50 eV. Only this non-ideal plasma explains the measured exceptional high fusion reactions of HB11 with profound reconfirmation as avalanche process. The related studies included the non-ideal plasmas for further interpretations.

The non-equilibrium and nonlinear states of plasmas are crucial.