In a recent report, the National Academies of Science, Engineering, and Medicine (NASEM) recommends that "the United States should start a national program of accompanying research and technology leading to the construction of a compact pilot plant that produces electricity from fusion at the lowest possible capital cost." It is generally acknowledged that a decarbonization of the world's energy system is unavoidable to combat climate change. While an exothermic chemical reaction such as the combustion of fossil fuels produces an energy of <1 eV per molecule, a nuclear fusion reaction is an attractive alternative as it releases 10 million times more energy. To date, considerable effort has been devoted to research involving the fusion between the nuclei of the two heavy isotopes of hydrogen: deuterium (D) and tritium (T). However, the main roadblock for the adoption of this technology is the need to heat the fuel to temperatures in the order of 50 million Kelvin and to keep it stable under extreme pressure conditions. Recent results show that this difficulty can be overcome by utilizing the nonthermal radiation pressure that can be generated via chirped-pulse amplifier laser systems and can trigger the fusion of hydrogen and boron-11 nuclei, producing clean energy in the form of kinetic alpha particles, thus sidestepping nuclear radiation problems due to the aneutronic nature of the process. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License.

As first disclosed by Project Daedalus, a very exciting approach for extensive space exploration uses Inertial Confinement Fusion (ICF) propulsion. Basically a small pellet of fusion fuel (with a diameter of a couple of millimeters) would be ignited by an electron beam or a laser. To produce a directed thrust, a magnetic field was employed to form the pusher plate. In principle, an aneutronic fusion reaction such as p-B11 could be used to maximize the energy in charged particles and to minimize radiation hazards. However due to the increased laser energy supposedly needed, most prior design studies like this have focused on DT fusion. For example, in the 1980s, LLNL and NASA studied an ICF-powered "Vehicle for Interplanetary Transport Applications" (VISTA). The conical VISTA spacecraft could deliver a hundred-tonne payload to Mars orbit and return to Earth in 130 days, or to Jupiter orbit and back in 403 days. Forty-one tonnes of deuterium/tritium (DT) fusion fuel was required, plus 4,124 tonnes of hydrogen expellant. The exhaust velocity obtained was 157 km/s. In the present study we propose a way to use p-B11 fusion to significantly improve this performance and essentially eliminate the associated radiological hazards.

The importance of the development of chirped pulse amplification (CPA) was highlighted with the award of the 2018 Nobel Prize in Physics to Gerard Mourou and Donna Strickland. CPA laser physics opens the way to exciting new advances in laser applications including laser fusion. As noted in this paper, its application to laser fusion enables ultrahigh power levels for ignition of laser fusion systems without requiring thermal pressures and millions of degrees centigrade. Instead, nonthermal pressures are driven by nonlinear force to create ultrahigh picosecond acceleration of plasma blocks. This paper discusses the exciting possibility of using CPA with block ignition to provide a new route for burning the environmentally clean fusion of hydrogen?boron-11 (HB-11) fuel.

To avoid the > 50 million degree temperatures in pressures for fusion, the goal has now been reached that higher pressures from picosecond CPA-laser pulses of more than 10 PW power can ignite nuclear fusion at modest temperatures in a power reactor for generating electricity.Gerard Mourou, who was honoured with the 2018 Physics Nobel Prize, was involved to solve this crucial problem of fusion energy with the reactor design as co-authors (Hora, H.,

Edward Teller Lectures, pp. 337-351 (2005) No Access30 years LASER INTERACTION AND RELATED PLASMA PHENOMENAHeinrich HoraHeinrich HoraDepartment of Theoretical Physics, University of New South Wales, Sydney 2052, Australiahttps://doi.org/10.1142/9781860947278_0025Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: The following sections are included: FUSION ENERGY ADIABATIC SELF SIMILARITY COMPRESSION AND IGNITION LASER DESIGN THE STORY OF ION ACCELERATION AND LASER ACCELERATION OF ELECTRONS THEORY OF FORCES AND INSTABILITIES PAIR PRODUCTION RELATED PLASMA PHENOMENA FINAL REMARKS Dedicated to Professor Edward Teller to his 90th birthday on January 15, 1998. FiguresReferencesRelatedDetails Edward Teller LecturesMetrics History PDF download

Recent experiments done at Prague with the 600 J/0.2 ns PALS laser interacting with a layer of boron dopants in a hydrogen enriched target have produced around 109 alphas. We suggest that these unexpected very high fusion reactions of proton with 11B indicate an avalanche multiplication for the measured anomalously high nuclear reaction yields. This can be explained by elastic nuclear collisions in the broad 600 keV energy band, which is coincident with the high nuclear p-11B fusion cross section, by the way of multiplication through generation of three secondary alpha particles from a single primarily produced alpha particle.

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.

Evaluation of nuclear binding energies from theory close to available measurements of a very high number of superheavy elements (SHE) based on α-decay energies Qα, arrived at a closing shell with a significant neutron number 184. Within the option of several discussed magic numbers for protons of around 120, Bagge's numbers 126 and 184 fit well and are supported by the element generation measurements by low energy nuclear reactions (LENR) discovered in deuterium loaded host metals. These measurements were showing a Maruhn–Greiner maximum from fission of compound nuclei in an excited state with double magic numbers for mutual confirmation.

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.

Laser ignition of fusion (LIF) of light nuclei for fusion reactions for producing energy (LIFE) by using very powerful laser pulses with duration in the range of picoseconds is the aim of fast ignition where HiPER is one of the options. Special attention is given to the ultrahigh acceleration of plasma blocks about which option results are reported including an alternative scheme for avoiding lateral energy losses. Examples of relativistic accelerations are evaluated for HiPER and LIFE applications.

Physics defines the reasons why laser driven ICF by laser pulses of nanosecond duration is basically different from the use of picosecond length. High intensity picoseconds laser pulses transfer energy directly into kinetic energy of plasma blocks without thermal losses, without delays by collisions and with exclusion of most instabilities. Following the long known theory by the nonlinear (ponderomotive) force, it was predicted that the plasma receives an ultra-high predicted acceleration first measured by Sauerbrey and theoretically confirmed in all details. Interaction of the plasma blocks with solid state fusion fuel should generate a Chu-Bobin fusion flame. Usng hydrodynamics with separate electron and ion fluids, detales properties can be studied about shock generation, and the varying velocity of the flame fronts far above 1000 km/s for high gains.

In this research, we presented the application of picosecond terawatt laser pulses for ultrahigh acceleration of plasma blocks for fast ignition of fusion. Ultrahigh acceleration of plasma blocks after irradiation of picosecond laser pulses of around terawatt power in the range of 10 20  cm/s 2 was discovered by Sauerbrey (1996) as measured by Doppler effect where the laser intensity was up to about 10 18 W/cm 2 . This is several orders of magnitude higher than acceleration by irradiation based on thermal interaction of lasers has produced. This ultrahigh acceleration resulted from hydrodynamic computations at plane target interaction in 1978 at comparable conditions where the interaction was dominated by the nonlinear (generalized ponderomotive) forces where the laser energy was instantly converted into plasma motion in contrast to slow and delayed thermal collision processes. After clarifying this basic result, the application of the plasma blocks for side-on ignition of solid density or modestly compressed fusion fuel following the theory of Chu (1971) is updated in view of later discovered plasma properties and the ignition of deuterium tritium and of proton- 11 B appeared possible for a dozen of PW-PS laser pulses if an extremely high contrast ratio avoided relativistic self-focusing. A re-evaluation of more recent experiment confirms the acceleration by the nonlinear force, and the generation of the fusion flame with properties of Rankine-Hugoniot shocks is reported.

The new possibility of side-on laser ignition of p-B-11 with negligible radioactivity encouraged to study the fusion of solid state p-Li-7 fuel that again turns out to be only about 10 times more difficult than the side-on ignition of solid deuterium-tritium using petawatt-picosecond laser pulses at anomalous interaction conditions if very high contrast ratio. Updated cross sections of the nuclear reaction are included.

Interaction of picosecond laser pulses above terawatt power with high density plasmas shows a nearly 100% conversion of the laser energy into directed acceleration of the electron cloud by nonlinear (ponderomotive) forces giving the ion cloud accelerations several orders of magnitude higher than comparable nanosecond interaction based on thermal pressure processes.

A fundamental different mechanism dominates laser interaction with picosecond-terawatt pulses in contrast to the thermalpressure processes with ns pulses. At ps-interaction, the thermal effects are mostly diminished and the nonlinear (ponderomotive) forces convert laser energy instantly with nearly 100% efficiency into the space charge neutral electron cloud, whose motion is determined by the inertia of the attached ion cloud. These facts were realized only by steps in the past and are expressed by the ultrahigh plasma acceleration, which is more than few thousand times higher than observed by any thermokinetic mechanism. The subsequent application for side-on ignition of uncompressed fusion fuel by the ultrahigh accelerated plasma blocks is studied for the first time by using the genuine two-fluid hydrodynamics. Details of the shock-like flame propagation can be evaluated for the transition to ignition conditions at velocities near 2000 km/s for solid deuterium-tritium.

The hot spot heating process by an assumed deuteron beam is evaluated in order to estimate the contribution of the energy produced by the deuteron beam-target fusion to the heating process. The deuteron beam energy versus the number of deuterons is evaluated through the experimentally achieved proton beam energy distribution using the TRIDENT short pulse laser at the Los Alamos National Laboratory (LANL). The corresponding hot spot heating is then calculated using this assumed deuteron beam spectrum. The resulting first order heating dynamics is employed in the expanded "bonus" energy calculation, and a 12.73% extra energy from deuteron beam-target fusion was found with the assumed deuteron spectrum when rho r(b) = 4.5 g/cm(2) is considered, where. is the fuel density, and r(b) is the ion beam focusing radius on the target. The results provide further insight into the contribution of the extra heat produced by deuteron beam-target fusion to the hot spot ignition process. A further analysis of how a converter foil using ultra-high-density cluster materials can help to achieve the yield requirements for ignition is presented.

Nonlinear effects in laser-plasma interaction are of particular interest in the study of nuclear fusion. The nonlinear force is derived using symplectic geometry for the Hamiltonian formulation of the force density as gradients of the energy density.

Use of laser-driven Inertial Confinement Fusion (ICF) for space propulsion has been examined in several earlier conceptual design studies. However, these designs used older ICF target technology. Important new directions opened following the development of “chirped” lasers capable of ultra-short ps pulses with powers of PWs. This allows fast ignition (FI) for high energy gain ICF power plants. The FI approach uses a conventional laser to precompress the target to high density. In the deuteron beam version, the PW laser is then fired on a converter plate in front of the ICF target, creating an intense deuteron ion beam that ignites fusion in a central core of the target. It is estimated that using a 10 TW-ps laser for FI can achieve fusion energy gains >103. Application of deuteron beam fast ignition to the earlier VISTA design for ICF space propulsion unit is considered here.