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LASNEX
LASNEX is a computer program that simulates the interactions between x-rays and a plasma, along with many effects associated with these interactions. The program is used to predict the performance of inertial confinement fusion (ICF) devices such as the Nova laser or proposed particle beam "drivers". Versions of LASNEX have been used since the late 1960s or early 1970s, and the program has been constantly updated. LASNEX's existence was mentioned in John Nuckolls' seminal paper in '' Nature'' in 1972 that first widely introduced the ICF concept, saying it was "...like breaking an enemy code. It tells you how many divisions to bring to bear on a problem." LASNEX uses a 2-dimensional finite element method (FEM) for calculations, breaking down the experimental area into a grid of arbitrary polygons. Each node on the grid records values for various parameters in the simulation. Values for thermal (low-energy) electrons and ions, super-thermal (high-energy and relativistic) elec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Ignition Facility
The National Ignition Facility (NIF) is a laser-based inertial confinement fusion (ICF) research device, located at Lawrence Livermore National Laboratory in Livermore, California, United States. NIF's mission is to achieve fusion ignition with high energy gain. It achieved the first scientific breakeven controlled fusion experiment on December 5, 2022, with an energy gain factor of 1.5. It supports nuclear weapon maintenance and design by studying the behavior of matter under the conditions found within nuclear explosions. NIF is the largest and most powerful ICF device built to date. The basic ICF concept is to squeeze a small amount of fuel to reach pressure and temperature necessary for fusion. NIF hosts the world's most energetic laser. The laser heats the outer layer of a small sphere. The energy is so intense that it causes the sphere to implode, squeezing the fuel inside. The implosion reaches a peak speed of , raising the fuel density from about that of water to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nova Laser
Nova was a high-power laser built at the Lawrence Livermore National Laboratory (LLNL) in California, United States, in 1984 which conducted advanced inertial confinement fusion (ICF) experiments until its dismantling in 1999. Nova was the first ICF experiment built with the intention of reaching "ignition", a chain reaction of nuclear fusion that releases a large amount of energy. Although Nova failed in this goal, the data it generated clearly defined the problem as being mostly a result of Rayleigh–Taylor instability, leading to the design of the National Ignition Facility, Nova's successor. Nova also generated considerable amounts of data on high-density matter physics, regardless of the lack of ignition, which is useful both in fusion power and nuclear weapons research. Background Inertial confinement fusion (ICF) devices use ''drivers'' to rapidly heat the outer layers of a ''target'' in order to compress it. The target is a small spherical pellet containing a few mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerodynamics
Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics. The term ''aerodynamics'' is often used synonymously with gas dynamics, the difference being that "gas dynamics" applies to the study of the motion of all gases, and is not limited to air. The formal study of aerodynamics began in the modern sense in the eighteenth century, although observations of fundamental concepts such as aerodynamic drag were recorded much earlier. Most of the early efforts in aerodynamics were directed toward achieving heavier-than-air flight, which was first demonstrated by Otto Lilienthal in 1891. Since then, the use of aerodynamics through mathematical analysis, empirical approximations, wind tunnel experimentation, and computer simulations has formed a rational basis f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Fusion
Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles (neutrons or protons). The difference in mass between the reactants and products is manifested as either the release or absorption of energy. This difference in mass arises due to the difference in nuclear binding energy between the atomic nuclei before and after the reaction. Nuclear fusion is the process that powers active or main-sequence stars and other high-magnitude stars, where large amounts of energy are released. A nuclear fusion process that produces atomic nuclei lighter than iron-56 or nickel-62 will generally release energy. These elements have a relatively small mass and a relatively large binding energy per nucleon. Fusion of nuclei lighter than these releases energy (an exothermic process), while the fusion of heavier nuclei results in energy retained by the product nucleons, and the resulting reaction is end ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hohlraum
In radiation thermodynamics, a hohlraum (a non-specific German word for a "hollow space" or "cavity") is a cavity whose walls are in radiative equilibrium with the radiant energy within the cavity. This idealized cavity can be approximated in practice by making a small perforation in the wall of a hollow container of any opaque material. The radiation escaping through such a perforation will be a good approximation to black-body radiation at the temperature of the interior of the container. Inertial confinement fusion The indirect drive approach to inertial confinement fusion is as follows: the fusion fuel capsule is held inside a cylindrical hohlraum. The hohlraum body is manufactured using a high-Z (high atomic number) element, usually gold or uranium. Inside the hohlraum is a fuel capsule containing deuterium and tritium (D-T) fuel. A frozen layer of D-T ice adheres inside the fuel capsule. The fuel capsule wall is synthesized using light elements such as plastic, beryllium, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Department Of Energy
The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and manages the research and development of nuclear power and nuclear weapons in the United States. The DOE oversees the U.S. nuclear weapons program, nuclear reactor production for the United States Navy, energy-related research, and domestic energy production and energy conservation. The DOE was created in 1977 in the aftermath of the 1973 oil crisis. It sponsors more physical science research than any other U.S. federal agency, the majority of which is conducted through its system of National Laboratories. The DOE also directs research in genomics, with the Human Genome Project originating from a DOE initiative. The department is headed by the Secretary of Energy, who reports directly to the president of the United States and is a member of the Cabinet. The current Secretary of Energy is Jennifer Granholm, who has serv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid digital subscribers. It also is a producer of popular podcasts such as '' The Daily''. Founded in 1851 by Henry Jarvis Raymond and George Jones, it was initially published by Raymond, Jones & Company. The ''Times'' has won 132 Pulitzer Prizes, the most of any newspaper, and has long been regarded as a national "newspaper of record". For print it is ranked 18th in the world by circulation and 3rd in the U.S. The paper is owned by the New York Times Company, which is publicly traded. It has been governed by the Sulzberger family since 1896, through a dual-class share structure after its shares became publicly traded. A. G. Sulzberger, the paper's publisher and the company's chairman, is the fifth generation of the family to head the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rayleigh–Taylor Instability
The Rayleigh–Taylor instability, or RT instability (after Lord Rayleigh and G. I. Taylor), is an instability of an interface between two fluids of different densities which occurs when the lighter fluid is pushing the heavier fluid. Drazin (2002) pp. 50–51. Examples include the behavior of water suspended above oil in the gravity of Earth, mushroom clouds like those from volcanic eruptions and atmospheric nuclear explosions, supernova explosions in which expanding core gas is accelerated into denser shell gas, instabilities in plasma fusion reactors and inertial confinement fusion. Water suspended atop oil is an everyday example of Rayleigh–Taylor instability, and it may be modeled by two completely plane-parallel layers of immiscible fluid, the denser fluid on top of the less dense one and both subject to the Earth's gravity. The equilibrium here is unstable to any perturbations or disturbances of the interface: if a parcel of heavier fluid is displaced downw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shiva Laser
The Shiva laser was a powerful 20-beam infrared neodymium glass (silica glass) laser built at Lawrence Livermore National Laboratory in 1977 for the study of inertial confinement fusion (ICF) and long-scale-length laser-plasma interactions. Presumably, the device was named after the multi-armed form of the Hindu god Shiva, due to the laser's multi-beamed structure. Shiva was instrumental in demonstrating a particular problem in compressing targets with lasers, leading to a major new device being constructed to address these problems, the Nova laser. Background The basic idea of any ICF device is to rapidly heat the outer layers of a "target", normally a small plastic sphere containing a few milligrams of fusion fuel, typically a mix of deuterium and tritium. The heat burns the plastic into a plasma, which explodes off the surface. Due to Newton's Third Law, the remaining portion of the target is driven inwards, eventually collapsing into a small point of very high density. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fusion Ignition
Fusion ignition is the point at which a nuclear fusion reaction becomes self-sustaining. This occurs when the energy being given off by the reaction heats the fuel mass more rapidly than it cools. In other words, fusion ignition is the point at which the increasing self-heating of the nuclear fusion removes the need for external heating. This is measured by the fusion energy gain factor. In the laboratory, fusion ignition was first achieved by the U.S. National Ignition Facility in 2021 and 2022. Research Ignition should not be confused with ''breakeven'', a similar concept that compares the total energy being given off to the energy being used to heat the fuel. The key difference is that breakeven ignores losses to the surroundings, which do not contribute to heating the fuel, and thus are not able to make the reaction self-sustaining. Breakeven is an important goal in the fusion energy field, but ignition is required for a practical energy producing design. In nature, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Program
A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components. A computer program in its human-readable form is called source code. Source code needs another computer program to execute because computers can only execute their native machine instructions. Therefore, source code may be translated to machine instructions using the language's compiler. (Assembly language programs are translated using an assembler.) The resulting file is called an executable. Alternatively, source code may execute within the language's interpreter. If the executable is requested for execution, then the operating system loads it into memory and starts a process. The central processing unit will soon switch to this process so it can fetch, decode, and then execute each machine instruction. If the source code is requested for e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Simulation
Computer simulation is the process of mathematical modelling, performed on a computer, which is designed to predict the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be determined by comparing their results to the real-world outcomes they aim to predict. Computer simulations have become a useful tool for the mathematical modeling of many natural systems in physics ( computational physics), astrophysics, climatology, chemistry, biology and manufacturing, as well as human systems in economics, psychology, social science, health care and engineering. Simulation of a system is represented as the running of the system's model. It can be used to explore and gain new insights into new technology and to estimate the performance of systems too complex for analytical solutions. Computer simulations are realized by running computer programs that can be either small, running almost instantly on small devices, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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