Shulou(Shulou.com)12/24 Report--

Thanks to CTOnews.com netizens, assassins for their clues delivery! A year ago, humans achieved the net energy gain of nuclear fusion for the first time. During the year, NIF continued to improve and successfully ignited three times, breaking multiple records in a row. Just recently, the chief scientist of the project was selected as one of the top ten people of the year in Nature.

The United States controlled nuclear fusion experiment, four times to achieve net energy gain!

On December 14 last year, Lawrence Livermore National Laboratory (LLNL) successfully ignited controllable fusion for the first time, removing the holy grail of clean energy for all mankind.

After providing 2.05 megajoules (MJ) of energy to the target, a fusion energy output of 3.15 megajoules is produced, with an energy gain of about 1.5.

On July 30, 2023, the laboratory achieved an all-time high of 3.88 megajoules of energy output for the first time.

On October 30, the laboratory re-recorded that the input energy reached 2.2 megajoules for the first time. At the same time, 3.4 megajoules ranked second in output energy.

In the face of successful "ignition" again and again, Nature also excitedly wrote that laser nuclear fusion is about to enter a new era.

It is conceivable that when controlled nuclear fusion is finally realized, it will be possible for mankind to gain access to large amounts of carbon-free clean energy for the first time in history, completely changing the energy roadmap of the future.

In other words, at that time, there will be no more greenhouse gases from the burning of coal and oil, no more dangerous, long-lasting radioactive waste-mankind will get real "clean energy".

This means that after entering the electrical era, the problem of energy shortage that has been troubling human beings will disappear from then on. Human beings can even achieve unprecedented scientific and technological breakthroughs in the constant star energy brought by controllable nuclear fusion.

Four successful fires, setting a new record in a row, but let's get back to reality.

The real difficulty in getting lasers to provide such a huge amount of energy is how to protect NIF's precious optics from debris.

NIF is the only laser system in the world that can operate above the damage threshold, which is partly due to the optical recycling system developed in the laboratory.

Enhanced Optical elements in June 2023, NIF completed two key improvements, which are critical to achieving an input energy of 2.2 megajoules.

This includes the use of fused silica debris shielding on the beamlines of NIF 2/3 and the installation of metal shields on 32 lower hemispherical beamlines.

These improvements reduce the damage rate caused by debris by 10 to 100 times, depending on the beamline. Due to gravity, the optical elements of the lower beam line receive the most fragments from the target chamber.

In addition, other improvements include new antireflective coatings, steam hexamethyldisiloxane (HMDS) treatment and increased recycling capacity for optical recovery. And a new "gray edge blocker" to solve a problem that scientists have not yet fully determined.

It is not just the increase in energy that is not enough to maintain the amazing breakthroughs made by NIF in the field of science.

The duration of the laser pulse is only a few billionths of a second, so a high degree of accuracy is needed to achieve the desired effect.

To achieve this goal, the team recently completed the deployment of a high-fidelity pulse shaping (HiFiPS) system.

As a multi-year project, HiFiPS can achieve more accurate and accurate pulse shaping, thus achieving better power balance and symmetry control in implosion.

In addition, the team renovated the optical fiber in the facility to make it more resistant to repeated neutron exposure. These fibers are used to accurately measure the laser pulses transmitted to the target.

After the renovation, the signal strength has been directly increased by 10 to 100 times, and researchers have been able to continue to "observe" laser performance accurately.

However, there is still a long way to go from the current level of technology to the realization of providing fusion energy to the grid.

Although NIF has the largest laser in the world, the system is so inefficient that more than 99% of the energy in each ignition is lost before reaching the target.

The development of more efficient laser systems is an important goal of DOE's newly launched inertial fusion research program.

Recently, the department announced that it would invest $42 million over four years to establish three new research centers to work together to achieve this goal and other scientific advances.

Each center will include national laboratories, university researchers and industry partners.

The chief scientist, physicist Annie Kritcher, who was selected as one of the top ten scientific people of the Nature and one of the core figures of the entire nuclear fusion program, was also selected as one of the top ten scientific people of the year in Nature.

In 2022, Annie Kritcher achieved on the National Ignition device (NIF) a goal that has been elusive in laboratories around the world for decades-to compress atoms to the extreme, causing their nuclei to fuse and generate more energy than the reaction itself consumes.

However, after reaching this experimental milestone (that is, ignition), the team is under pressure to repeat this achievement.

High-risk research is rarely plain sailing: the team made its first reappearance in June, but the results were far from satisfactory.

Fortunately, the third attempt was a success. On July 30, NIF's 192 laser beams fired 2.05 megajoules of energy at hydrogen isotope deuterium and tritium spheres frozen in gold cylinders.

The resulting implosion releases energy during the fusion of isotopes into helium and produces temperatures six times that of the sun's core. In the end, these created a record-breaking 3.88 megajoule fusion energy.

Looking at the world, before NIF achieved this achievement, no laboratory could achieve a fusion reaction in which the output energy was greater than the energy consumption.

Kritcher and her team then successfully ignited twice in October, bringing the total number of fires to four.

Kritcher began working on fusion energy during a summer internship in Livermore in 2004. Soon she set her sights on one of the few places in the NIF-- world where fusion reactions can be studied.

In 2012, Kritcher officially joined NIF.

Since then, she has led the team to analyze experimental data and use computer models to design experiments-to achieve and increase fusion production by adjusting parameters such as the size and configuration of targets and the energy and time of various laser beams. Once her team has completed the design, the experimental team will take over the emission of lasers and collect data.

In the process, Kritcher showed great ability, which made her one of the chief designers of NIF in 2016.

Over the next few years, Kritcher and her team have been working on digital operations and design adjustments to NIF's main experimental projects. While making various changes to the goal, the team also used various improvement measures to improve the overall energy of the laser. As a result, nuclear fusion is becoming more and more frequent.

With the success of Ignition, Kritcher began a series of new experiments-increasing production again by providing more laser energy to thicker target sacs.

This also represents another step forward for NIF to achieve its goal of producing tens of megajoules or more.

Controlled nuclear fusion, the holy grail of clean energy, simply put, nuclear fusion is the process in which two light nuclei combine to form a heavier nucleus and release a great deal of energy.

Two hydrogen atoms collide and polymerize into helium atoms, which have a slightly smaller mass than the original hydrogen atoms. According to Einstein's iconic E=mc ²mass-energy equation, this mass difference translates into an energy burst.

At the core of the sun, nuclear fusion of 620 million tons of hydrogen takes place every second. The energy generated is the source of all life on earth.

But one of the big problems in the use of nuclear fusion is how to make the energy released by the fusion reaction greater than the input energy and make the process sustainable.

The principle of NIF Ignition in the 1960s, a group of pioneer scientists at LLNL hypothesized that lasers could be used to induce nuclear fusion in laboratory environments.

Then, under the leadership of physicist John Nuckolls, this revolutionary idea evolved into inertial confinement fusion.

In order to realize this concept, LLNL established a series of more and more powerful laser systems, and finally established the largest and most powerful NIF in the world.

In the experiment, the laser mimics the conditions in the center of the sun, fusing heavy hydrogen isotopes, deuterium and tritium into helium.

First, a number of hydrogen balls are placed in a device the size of pepper grains, and then a powerful 192 lasers are used to heat and compress the hydrogen fuel.

After entering the annulus, the laser hits the inner wall and causes it to emit X-rays, which can then heat it to 100 million degrees Celsius-hotter than the center of the sun and compress it to more than 100 billion times the earth's atmospheric pressure.

High-energy laser will make the surface of the ball plasticized, and the rest of the central material driven by Newton's third law will eventually collapse to the center and implode.

During implosion, as long as the fuel ball is given the right high temperature and high pressure, a chain reaction-that is, "ignition"-can occur, and a large amount of energy will be released.

The National Ignition device (NIF), which is an engineering miracle that makes these things a reality, is also a great achievement in engineering and technology.

Material scientists and laser physicists worked with engineers to design a facility containing 7500 large optical elements, 26000 small optical elements and more than 66000 control points.

These optical elements and other components are contained in about 6200 complex modular devices called production line interchangeable units (LRUs). It can be replaced quickly when necessary to ensure the continuous operation of the facility.

The NIF laser pulse is formed from the initial pulse of the main oscillator chamber to the target, which takes one kilometer and takes 4.5 microseconds. The time to reach the center of the target room is 30 picoseconds with an accuracy of 50 microns.

To achieve such absolute accuracy of pointing to stability and objectives, it is a great challenge in engineering design. Optical support systems are required to have rock-solid stability, accurate positioning and alignment of components, and strict and accurate computer timing systems.

In order to meet these challenges, all structures that support NIF mirrors and lenses are designed with high stability in mind.

The engineering team carefully calculated the possible effects on laser components (usually laser mirrors) for all vibration sources, including pumps, motors, and transformers.

Through meticulous modeling, vibration (> 1Hz) and drift (

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