The US Department of Energy announces a milestone achievement: the world‘s first successful laser fusion ignition

    ·US Secretary of Energy Jennifer Graham stated in a statement that this breakthrough is a "milestone achievement". This achievement is expected to help humanity take a crucial step towards achieving zero carbon emitting energy.

    Experiment on December 5th

    Nuclear fusion reaction is a common phenomenon in the universe, which is the energy source of stars (such as the sun). Nuclear fusion energy is also the forefront direction of global energy development and is regarded as the "ultimate energy" of future society. If humans can control this energy, they can overcome the current energy and environmental crisis on Earth.

    The $3.5 billion US National Ignition Device is located at the Lawrence Livermore National Laboratory, initially designed to test nuclear weapons through simulated explosions and later used to advance fusion energy research. The NIF, which covers an area of three football fields, began official ignition experiments in 2010. The United States has been continuously hitting the ignition targets for more than 10 years, and the process has been twists and turns.

    In 2014, scientists at Lawrence Livermore National Laboratory achieved results, but the energy generated at that time was very small, equivalent to the energy consumed by a 60 watt light bulb in 5 minutes. In August 2021, NIF generated 1.37 megajoules of energy in a fusion reaction, approximately 70% of the laser energy, making it the closest net energy gain in the world.

    On the morning of December 5, 2022 local time at 1:03 am, Lawrence Livermore National Laboratory used 192 powerful laser beams to hit a solid target of hydrogen isotopes only the size of pepper. The experiment inputted 2.05 megajoules of energy into the target, resulting in a fusion energy output of 3.15 megajoules and an energy gain of 153%.

    The working principle of nuclear fusion. Image source: BBC American technology media The Verge commented that using nuclear fusion may be revolutionary - providing people with abundant energy without being exposed to harmful side effects such as greenhouse gas emissions or persistent radioactive waste. However, doing so depends on overcoming significant engineering obstacles. After decades of experimentation, this announcement represents a small but significant victory over one of these obstacles. However, there is still a long way to go to achieve any dream of clean energy.

    With real investment and real attention, this time scale can be closer, "said Budier, director of Lawrence Livermore National Laboratory, at a press conference." We haven‘t been closer for a long time, have we? Because we need this basic first step. Therefore, we are in a good position today to start understanding what is needed next

    Firstly, scientists need to be able to ignite again. Budier said that there are still many things to be done, "you must be able to generate many, many fusion igniters every minute." "There are significant obstacles not only in terms of science, but also in terms of technology

    One obstacle is that any laser used in future work needs to be more efficient. The national ignition device used in this experiment is the world‘s largest and highest energy laser, but it is still based on technology from the 1980s. Modern lasers have higher efficiency, and future efforts may attempt to incorporate new technologies into experiments.

    This indicates that this is achievable. Crossing this threshold allows them to start researching better lasers, more efficient lasers, better sealed capsules, etc. We need the private sector to participate. It is really important for so much US public funding to enter this breakthrough, but all necessary steps we will take to bring it to commercial level still require both public and private research

    The staff at Lawrence Livermore National Laboratory are working. What is nuclear fusion?

    Nuclear fusion is a form of nuclear reaction that combines two lighter nuclei to form a heavier nucleus and a very light nucleus (or particle). During the fusion process, two lighter nuclei produce mass loss and release enormous energy. When two light nuclei undergo fusion, they repel each other due to their positive charge. However, when two nuclei with high enough energy meet head-on, they can gather quite tightly, so that the nuclear force can overcome Coulomb repulsion and undergo a nuclear reaction, which is called nuclear fusion.

    The internal temperature of the sun and many stars is as high as tens of millions of degrees Celsius, and intense nuclear fusion reactions occur every moment. The energy emitted by the sun per second is approximately 3.9 × 10 ^ 26 joules, although only one billionth of the energy released by the sun per second reaches the surface of the Earth, it is also a huge amount of energy that makes all life activities on Earth possible.

    Nuclear fusion energy is also the forefront direction of energy development worldwide. Due to its fuel coming from seawater, efficiency tens of millions of times higher than fossil energy, no long-term nuclear waste, and no carbon emissions, nuclear fusion energy is considered the "ultimate energy" of future society. If humans can control this energy, they can overcome the current energy and environmental crisis on Earth.

    The raw materials required for controllable nuclear fusion are the two isotopes of hydrogen, deuterium and tritium. Deuterium can be extracted from seawater, and tritium can be generated from lithium, which is abundant in reserves on Earth. The energy generated by the fusion reaction of deuterium in one cubic kilometer of seawater is equivalent to the total energy generated by all oil reserves on Earth.

    But if humans want to successfully achieve controlled thermonuclear fusion reactions on Earth and obtain enormous energy, they must create three necessary conditions. One is the extremely high temperature, which makes deuterium and tritium fuel a hot plasma exceeding 100 million degrees Celsius; The second is the extremely high density, which increases the probability of quantum tunneling of deuterium tritium nuclei and facilitates the retention of alpha particle energy generated by fusion to continue participating in nuclear fusion reactions; The third is that the plasma is constrained in a limited space for a sufficiently long time.

    So far, human research on controlled nuclear fusion has mainly been divided into two categories. One is magnetic confinement fusion, which uses a special form of magnetic field to constrain the ultra-high temperature plasma composed of light atomic nuclei such as deuterium and tritium and free electrons in a thermonuclear reaction state within a limited volume, causing it to undergo a large number of controlled atomic fusion reactions and release energy. A typical experimental device is the fully superconducting Tokamak nuclear fusion experimental device (EAST) of the Hefei Institute of Materials Science, Chinese Academy of Sciences. The second is laser nuclear fusion, which is an inertial confinement nuclear fusion driven by high-power lasers. Typical experimental devices such as China‘s Shenguang Laser Device and the United States‘ National Ignition Device.