A5035754092- Laser-Plasma Interactions and Diagnostics
- Nuclear Physics and Applications
- Magnetic confinement fusion research
- Laser-induced spectroscopy and plasma
- Nuclear reactor physics and engineering
- High-pressure geophysics and materials
- Combustion and Detonation Processes
- Cold Fusion and Nuclear Reactions
- Atomic and Molecular Physics
- Fusion materials and technologies
- Energetic Materials and Combustion
- Astro and Planetary Science
- Plasma Diagnostics and Applications
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Nuclear Materials and Properties
- Ion-surface interactions and analysis
- Quantum, superfluid, helium dynamics
- Nonlinear Dynamics and Pattern Formation
- Mass Spectrometry Techniques and Applications
- Atomic and Subatomic Physics Research
- Laser-Matter Interactions and Applications
- Mathematical Dynamics and Fractals
- stochastic dynamics and bifurcation
- Stability and Controllability of Differential Equations
Imperial College London
2016-2025
Imperial Valley College
2024
University of Rochester
2019-2020
Energetics (United States)
2019-2020
Los Alamos National Laboratory
2019
Massachusetts Institute of Technology
2019
University College Cork
2006-2009
For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as proof of principle various concepts. Following Lawson criterion, an ignited plasma is one where heating power high enough overcome all physical processes that cool plasma, creating positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, state can begin "burn propagation" into surrounding cold fuel, enabling possibility energy...
On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>G</a:mi></a:mrow><a:mrow><a:mtext>target</a:mtext></a:mrow></a:msub></a:mrow></a:math> of 1.5. This is first laboratory demonstration exceeding “scientific breakeven” (or <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"...
Significant broadening of the energy spectrum products nuclear reactions occurs in fusion plasmas. We provide a method for calculating shape this production arbitrary plasma distribution functions. The is exact and can be used both isotropic anisotropic distributions. derive expressions Maxwellian (both stationary moving with bulk fluid velocity), bi-Maxwellian beam–target neutron produced by D + → He3 n reaction studied as an example. It shown that from becomes asymmetric at high...
Three-dimensional extended-magnetohydrodynamic simulations of the stagnation phase inertial confinement fusion implosion experiments at National Ignition Facility are presented, showing self-generated magnetic fields over ${10}^{4}\text{ }\text{ }\mathrm{T}$. Angular high mode-number perturbations develop large fields, but localized to cold, dense hot-spot surface, which is hard magnetize. When low-mode also present, injected into hot core, reaching significant magnetizations, with peak...
The application of an external 26 Tesla axial magnetic field to a D2 gas-filled capsule indirectly driven on the National Ignition Facility is observed increase ion temperature by 40% and neutron yield factor 3.2 in hot spot with areal density approaching what required for fusion ignition [1]. improvements are determined from energy spectral measurements 2.45 MeV neutrons D(d,n)3He reaction, compressed central core B estimated be ∼4.9 kT using 14.1 secondary D(T,n)4He reactions. experiments...
Recent experiments at the National Ignition Facility (NIF) have demonstrated ignition for first time in an inertial confinement fusion (ICF) experiment, a major milestone allowing possibility of high energy gain through burn propagation. Use external magnetic fields, applied primarily to reduce thermal losses, could increase hotspot temperature and ease requirements ignition, opening up capsule design space gain. However, this same restriction transport has potential inhibit propagation,...
Neutrons generated in Inertial Confinement Fusion (ICF) experiments provide valuable information to interpret the conditions reached plasma. The neutron time-of-flight (nToF) technique is well suited for measuring energy spectrum due short time (100 ps) over which neutrons are typically emitted ICF experiments. By locating detectors 10s of meters from source, can be measured high precision. We present a contextual review current state art nToF at facilities United States, outlining physics...
We present the results of 3D simulations indirect drive inertial confinement fusion capsules driven by “high-foot” radiation pulse on National Ignition Facility. The are post-processed using a semi-deterministic ray tracing model to generate synthetic deuterium-tritium (DT) and deuterium-deuterium (DD) neutron spectra as well primary down scattered images. Results with low-mode asymmetries used estimate magnitude anisotropy in shift, width, shape. Comparisons images highlight lack alignment...
Pre-magnetisation of inertial confinement fusion implosions on the National Ignition Facility has potential to raise current high-performing targets into ignition regime [Perkins et al. “The imposed magnetic fields for enhancing probability and energy yield in indirect-drive fusion,” Phys. Plasmas 24, 062708 (2017)]. A key concern with this method is that application a field inherently increases asymmetry. This paper uses 3-D extended-magnetohydrodynamics Gorgon simulations investigate how...
Magnetizing a cryogenic deuterium–tritium (DT)-layered inertial confinement fusion (ICF) implosion can improve performance by reducing thermal conduction and improving DT-alpha in the hot spot. A room-temperature, magnetized indirect-drive ICF platform at National Ignition Facility has been developed, using high-Z, high-resistivity AuTa4 alloy as hohlraum wall material. Experiments show 2.5× increase deuterium–deuterium (DD) neutron yield 0.8-keV hot-spot temperature with application of 12-T...
The goal of this article is twofold. first objective to demonstrate the role hysteresis in hydrology. second describe a class simple and convenient mathematical models hydrological systems with briefly discuss methods for quantitative qualitative analysis such models. This organized as follows. In section we Preisach model. We then present an explicit expression analogues wetting drying curves model context. central occupied by special one-parameter classes operators which are useful...
Understanding of the thermonuclear burn in an inertial confinement fusion implosion requires knowledge local deuterium–tritium (DT) fuel density. Neutron imaging core now provides this previously unavailable information. Two types neutron images are required. The first is image primary 14-MeV neutrons produced by D + T reaction. second that leave hot spot and downscattered to lower energy elastic inelastic collisions fuel. These measured gating detector record 6–12 MeV neutrons. Using...
Low-mode asymmetries have emerged as one of the primary challenges to achieving high-performing inertial confinement fusion (ICF) implosions. In direct-drive ICF, an important potential seed such is capsule stalk mount, impact which has remained a contentious question. this paper, we describe results from experiment on OMEGA laser with intentional offsets at varying angles clearly demonstrates mount implosion dynamics. The angle between and offset found significantly observables....
The kinematic lower bound for the single scattering of neutrons produced in DT fusion reactions produces a backscatter edge measured neutron spectrum. energy spectrum backscattered is dependent on ion velocity distribution. As preferentially scatter densest regions capsule, presents unique measurement hydrodynamic conditions dense fuel. It shown that spectral shape determined by rate weighted fluid and temperature stagnating capsule. In order to fit spectrum, model various backgrounds around...
We present 3D radiation-hydrodynamics simulations of indirect-drive inertial confinement fusion experiments performed at the National Ignition Facility (NIF). The are carried out on two shots from different NIF experimental campaigns: N130927 high foot series and N161023 ongoing density carbon series. Applying representative perturbation sources each implosion, synthetic nuclear diagnostics used to post-process infer stagnation parameters. underlying physical mechanisms that produce observed...
Low-mode asymmetries prevent effective compression, confinement, and heating of the fuel in inertial confinement fusion (ICF) implosions, their control is essential to achieving ignition. Ion temperatures (${T}_{\mathrm{ion}}$) ICF experiments are inferred from broadening primary neutron spectra. Directional motion (flow) at burn also impacts will lead artificially inflated ``${T}_{\mathrm{ion}}$'' values. Flow due low-mode expected give rise line-of-sight variations measured...
Low-mode asymmetries have emerged as one of the primary challenges to achieving high-performing inertial confinement fusion implosions. These seed flows in implosions, which will manifest modifications measured ion temperature (Tion) inferred from broadening neutron spectra. The effects are important understand (i) learn control and mitigate low-mode (ii) experimentally more closely capture thermal Tion used input implosion performance metric calculations. In this paper, results simulations...
High energy gain in inertial fusion schemes requires the propagation of a thermonuclear burn wave from hot to cold fuel. We consider problem when magnetic field is orthogonal wave. Using an extended-MHD model with magnetized α transport equation, we find that can reduce rate by suppressing electron thermal conduction and particle flux. Magnetic during subject competing effects: be advected regions ablation fuel, while Nernst flux effects These effects, combined temperature increase due burn,...
Diagnosing plasma magnetization in inertial confinement fusion implosions is important for understanding how magnetic fields affect implosion dynamics and to assess conditions magnetized experiments. Secondary deuterium–tritium (DT) reactions provide two diagnostic signatures infer neutron-averaged magnetization. Magnetically confining tritons from deuterium–deuterium (DD) the hot spot increases their path lengths energy loss, leading an increase secondary DT reaction yield. In addition,...
Recent inertial confinement fusion experiments have shown primary spectral moments which are incompatible with a Maxwellian velocity distribution description. These results show that an ion kinetic description of the reacting ions is necessary. We develop theoretical classification non-Maxwellian distributions using moments. At mesoscopic level, monoenergetic decomposition reveals there constraints on space accessible by isotropic distributions. General expressions for directionally...
The ion velocity distribution functions of thermonuclear plasmas generated by spherical laser direct drive implosions are studied using deuterium-tritium (DT) and deuterium-deuterium (DD) fusion neutron energy spectrum measurements. A hydrodynamic Maxwellian plasma model accurately describes measurements made from lower temperature (<10 keV), hydrodynamiclike plasmas, but is insufficient to describe higher more kineticlike plasmas. high consistent with Vlasov-Fokker-Planck (VFP) simulation...