If someone tells you that California has a huge laser related to space and defense, you might imagine it was a superweapon designed to blow up enemies. satellite from the sky. But the reality is completely different. The new laser is a unique research tool for scientists that can create the extreme states that exist inside stars and nuclear explosions.
Where is the largest laser in the world?
The giant laser is located at Lawrence Livermore National Laboratory (LLNL) in Livermore, California, and is known by the rather mysterious name National Ignition Facility (NIF). Because, in the context of nuclear science, “ignition” has a very specific meaning. Lawrence Livermore National Laboratory.. This is the point at which the fusion reaction becomes self-sustaining. This is a condition found inside the Sun and other stars, but it is very difficult to achieve in an Earth-bound laboratory.trigger Nuclear fusion Very high temperatures and pressures are required, which is where NIF’s giant lasers come into play.
The NIF, which has been in operation since March 2009, fills a 10-story building that is the same size as three football fields. There are 192 individual laser beams that direct all energy to small targets less than a centimeter. It occurs in a single, carefully tuned pulse that lasts only a few billionths of a second. The resulting flash is a temperature of 180 million degrees Fahrenheit (100 million degrees Celsius) and EarthAtmosphere.
To understand how NIF has achieved such a phenomenal feat, it is worth exploring what a laser beam is.The word laser “Optical amplification by stimulated emission of radiation,” And it holds the key to how they work. Perhaps the most well-known example of amplification is the sound system. The system sends additional energy to the audio signal to increase volume, maintain accurate characteristics, and hear distortion-free results. In effect, that’s what the laser does — but Light Instead of sound.
In the case of NIF, the 192 laser beams are gradually amplified as they pass back and forth through the neodymium-doped phosphate glass slab. The energy of this amplification comes from a series of powerful flashlamps that surround the glass slab.Strong white light from these lamps is used to raise neodymium before the beam passes. atom To a higher energy level than usual.
Then, when the laser pulse passes through the glass, it triggers the “stimulated emission,” which is the acronym for laser. The excess energy of the neodymium atom is emitted in the form of more light waves, traveling in exactly the same direction as the original pulse and at the exact same wavelength. Therefore, the laser beam is gradually amplified in each pass and eventually becomes billions of times stronger than when the laser beam is incident.
Nuclear fusion power
Nuclear fusion is a reaction in which the nuclei of light atoms react as follows. hydrogen, Combine to create a heavy one like this helium..It is essential to life on earth because it empowers Sun, According to NASA, This is our main source of light and heat. For decades, scientists have endeavored to reproduce this process in a controlled, self-sustaining fusion reaction on Earth.
In many respects, this is a perfect energy source without the radioactive waste associated with traditional nuclear power plants, or carbon Emissions Fossil fuel According to the United Kingdom Atomic Energy Corporation.. Unfortunately, this proves an elusive goal, and the only fusion reaction ever put into practical use is the fiercely devastating one that powers thermonuclear weapons.
It was in this context that NIF was first established. NS The main purpose of LLNL It is about ensuring the safety, security, and reliability of America’s nuclear deterrence. In the past, this included aggressive development and testing of new weapons, but thankfully this is no longer the case. LLNL is currently striving to maintain the integrity of existing weapons without full-scale testing, and NIF plays an important role in this. It has the unique ability to create the enormous temperatures and pressures scientists need to study the internal state of exploding nuclear weapons.
Related: What is the Manhattan Project?
Weapons-related research still dominates NIF’s activities, but about 8% of that time is reserved for more peaceful experiments each year. These include research on fusion on the Sun and other stars, and research on technologies that may facilitate the use of fusion as a future power source on Earth. However, not all NIF experiments are related to fusion. Lasers create such extreme conditions in terms of temperature and pressure, so we study other situations where these conditions occur, such as the expanding shock waves around supernova explosions and the incredibly dense cores of giant planets. Can be used to
How does the laser work?
According to NIFIts ultimate goal is to focus all the energy from the powerful laser beam array on a pea-sized target. The laser does not fire continuously, but with a short pulse it is only one-twentieth of a second long. This is enough to raise the target to the huge temperatures and pressures researchers need.
It only takes a few microseconds from the initial creation of the laser pulse to the blasting of the target, but much happens in the meantime. First, one weak pulse is created in the master oscillator room. It is then split into a total of 192 separate beams within two giant laser bays, which are gradually amplified as they pass back and forth through the system. The energy for this comes from a super-powerful flashlamp that illuminates a series of glass slabs through which the beam passes, always gaining energy.
During the amplification process, all beams move in parallel, but when they are strong enough, they are rearranged into two cones within the target chamber. They converge from above and below to the target, all arriving at the same time and supplying energy in one large flash.
“I was overwhelmed by the size of the NIF laser, so I was almost fainted on my first visit,” he said. Jena My Neck, A plasma physicist studying the origin of the cosmic magnetic field at the National Ignition Facility. Standing next to it is like standing next to Niagara Falls. You feel paralyzed by the tremendous force of this machine that rises above you. Running an experiment at NIF is different from running an experiment at another laser facility. The conditions obtained are so extreme that, to some extent, we do not know what to expect. All you know is that something special is about to happen. “
The conditions created within the NIF’s target chamber far exceed those normally found on Earth, but are much more typical in certain astrophysical environments. This makes NIF an invaluable tool for space research. For example, the interior of a star fuses in much the same way as a nuclear explosion NIF was designed to emulate, but on a much larger scale. 2017, LLNL’s “Discovery Science” Program, It was used to create conditions similar to the interior of a star, allowing researchers to collect data that cannot be obtained by other means.
NIF is also used in physics research. Supernova The ubiquity of shock waves and cosmic magnetic fields. According to Dr. Meinecke, a series of NIF experiments has made it possible to explain the latter in terms of a phenomenon called the “turbulent dynamo” effect. “Fast-moving shock waves may be the birthplace of the ubiquitous magnetic fields in our universe,” Dr. Meinecke told us. “The strength of these magnetic fields increases until a unique phenomenon called a turbulent dynamo occurs. This is a regime of non-linear magnetic field amplification commonly observed in space, but on Earth by our team. It was just created in. ”
In the everyday world, dynamos are devices for converting mechanical energy into electromagnetic NIF’s experiments suggest that similar processes in the early universe were responsible for pushing the initially weak magnetic field to the strong magnetic field that is now penetrating the galaxy.
A supernova is a very powerful explosion that occurs when a large star runs out of nuclear fuel. They create extreme conditions not found anywhere else in the universe, which intrigues astronomers. Still, nearby supernovae are so rare that they are not fully understood. For example, scientists have been wondering how supernova shock waves can accelerate cosmic rays to near the speed of light. But thanks to NIF, the puzzle was solved.according to LLNLIn 2020, researchers used a giant laser to recreate a supernova-like state on a miniature scale and discovered that shock wave turbulence was responsible for the anomalous acceleration. This was something that could not be discovered by astronomical observation alone.
Another use for giant lasers is to compress materials at very high densities. This is much higher than that found on Earth, but is comparable to the following conditions in the center of a giant planet: Jupiter When Saturn..For example, it is used to study that method Under these conditions hydrogen turns into a metal.. And in 2014, we used NIF to squeeze the diamond crystals to a pressure comparable to the pressure in the center of Saturn. This is 14 times the pressure of the core of the earth itself. The specific challenge in this experiment was to avoid generating very high temperatures. These are desirable in fusion experiments, but unrealistic in the context of planetary cores.However, due to careful design, the experiment succeeded in compression. diamond To a density similar to lead – and in the process provided a wealth of data to planetary scientists.
It is also possible that NIF may have a completely different kind of practical space application. This is because fusion energy could be a viable option for spacecraft propulsion, in addition to its potential use here on Earth.Over the years, some possible designs ProposedHowever, most of these trigger fusion reactions in a completely different way than NIF.But in 2005 LLNL Scientist Charles Oath In collaboration with NASA, we have developed a space propulsion concept based on the same principles as NIF. Called VISTA for “vehicles for interplanetary transport,” this design employs a conical arrangement of laser beams to initiate fusion of a series of small fuel pellets, resulting in powerful thrust. Bend in the desired direction with assistance. magnet According to page 7 of Report by US Department of Energy..
World’s Largest Laser | Live Science
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