Controlled self-sustained nuclear fusion or new dawn - US scientists deduced nuclear fusion

Tokamak nuclear fusion loop device.

For a long time, there has been a magical phenomenon that researchers have failed to achieve controllable self-sustained nuclear fusion reactions. However, recently American physicists said they may have found a solution to the mystery. Researchers believe that if the newly proposed solution is validated experimentally, it will help people eliminate one of the major obstacles to the development of nuclear fusion and make nuclear fusion a clean and abundant source of electricity.

Nuclear fusion is difficult

In an in-depth analysis, scientists at the US Department of Energy’s Princeton Plasma Physics Laboratory targeted the high-temperature charged gases in nuclear fusion experiments—the tiny, bubble-like regions of the plasma called islands. These islands contain impurities that cool the plasma. Scientists believe that it is these islands that form the basis of the familiar "heat density limit" problem, which hinders the most efficient operation of nuclear fusion reactors.

When the plasma temperature and density are high enough, the contained nuclei bind and release energy, forming what people call nuclear fusion. However, when the plasma in the Tokamak ring experimental reactor reaches a mysterious “thermal density limit”, the plasma can rotate to form a flash and the temperature drops.

Scientists believe that the emergence of numerous islands in the plasma has caused double damage. In addition to causing the plasma temperature to drop, these islands also act like a shield to block more energy from heating the island's plasma. When the energy overflowing from the island exceeds the energy that can be added to the plasma by the ohmic heating process, the balance is broken. When the island grows large enough, the current used to help heat and confine the plasma heat collapses and the plasma spreads out.

David Gates is a physicist at the US Department of Energy's Princeton Plasma Physics Laboratory. He and a postdoctoral researcher at the US Department of Energy received a visiting professor from the Massachusetts Institute of Technology Plasma Science Center for Nuclear Fusion Luis Deltoto-Apparre. Qiou co-sponsored a solution to the "heat density boundary" problem of nuclear fusion. Gates said that it is puzzling why adding more heat to the plasma still can't get it to a higher heat density, which is critical because heat density is an important parameter for nuclear fusion.

Summarize new knowledge

Gates said that the theory they stumbled across was "10 minutes, ah, ha." By focusing on the islands in the plasma and the impurities that carry the energy, they figured out the corresponding equations on the office whiteboard. Impurities originate from particles generated when the plasma strikes the tokamak ring. Del Todo-Arpario said that when the density of the plasma reached the mysterious “heat density limit”, many islands containing impurities appeared in the plasma and disintegrated.

Martin Greenwald, a physicist at the Massachusetts Institute of Technology, deduced the equation describing the "heat density limit," and thus the "heat density limit" is also called the "Greenway boundary." Greenwald has his own explanation for the reasons for the “heat density limit”. He believes that when turbulence occurs and the edge of the plasma cools and the excessive ions squeeze into the craters of the plasma core, it will appear. "The thermal density limit" causes current instability and collapse. He said that there is considerable evidence to verify his views, but at the same time he admitted that his views are also inadequate and welcomes new ideas. The theory proposed by Gates and Del Todo-Arpario represents a new approach to trying to solve the “heat density boundary”.

Gates and Del Todo-Aparicchio integrated the clues that people had mastered over the past decades to establish their research model. Gates himself first heard of the "heat density limit" in 1993 when he was doing postdoctoral research at the Carham Nuclear Fusion Energy Center in Abington, England. In the early days, the "heat density limit" was named after the scientist of the Kahlham Fusion Energy Center, Jane Hugel, who detailed Gates's "heat density limit."

For the plasma island issue, scientists have published a separate paper. In the mid-1980s, the French physicist Paul Henri Tebout introduced radiation-formed islands at a conference, but it was not published in the magazine. About 10 years later, the German physicist Wolfgang Sutppu speculated that the island was related to the "heat density limit." Gates said that although Suterpamp did not directly associate the plasma island with the "heat density limit," his research article actually inspired his own research. In 1996, Gates and Sutherpamp performed tokamak experiments at the Max Planck Institute for Plasma Physics in Germany. They only entered the Princeton Plasma Physics Laboratory the following year.

In early 2011, the plasma island problem almost disappeared from Gates. However, a conversation with Delcado Aparruccio involving the plasma island in the Alcator C-Mod Tokamak rekindled his interest in the issue. Del Todo-Aparicchio mentioned that scientists in the Princeton Plasma Physics Laboratory observed the appearance of corkscrew-shaped air masses in the plasma for the first time in the 1980s. The German physicist Arthur Weller reported this. The first person in the phenomenon.

After the conversation, Gates asked Del Duo-Aparicchio to look at the articles of Tribute and Suterp. Eight months later, Del Todo-Apparzio sent an email to Gates explaining the behavior of the corkscrew-shaped air masses. What most excited Gates was the island growth equation, which implied the "heat density limit". It was an amendment to the English physicist Paul Rutherford's formula based on relevant research derived from the 1980s. Gates believes that if Suetkamp's understanding of the island is accurate, then this equation should describe the "heat density limit."

When Gates and Del Todo-Arpalichi performed calculations in the office, they found that they did not need the entire equation, but only focused on plasma electron density and island heat radiation, and deduced that the heat loss exceeded the electron density. The equation. This in turn helped them find the mechanism that is expected to be hidden behind the "heat density limit."

When talking about why scientists had failed to obtain a similar heat density boundary theory in the past, Gates believes that the answer lies in the process of permeating or disseminating relevant research ideas to the scientific community. The idea of ​​heat radiation forming islands has never been publicly reported, and people just view it as an interesting point of view. People often disseminate information through publications, but the concept of “heat density limit” did not initially spread.

Gates and Del Todo-Arpario hope to pass the experiment at the Massachusetts Institute of Technology's Tokamak nuclear fusion ring device called Alcator C-Mod and the San Diego General Atomics DIII-D Tokamak ring. Verify their theory. One of the goals is that they intend to understand whether they can achieve higher densities by directly injecting energy into the plasma islands. If we can increase the density, then the Tokamak ring of the future can achieve a very high heat density and achieve the temperature of 100 million degrees Celsius needed for nuclear fusion.

The challenge of conquering the "heat density limit" will provide an improved path for future Tokamak ring devices to achieve self-sustained nuclear fusion reaction power generation, including nuclear fusion devices that replace the International Thermonuclear Experimental Reactor (ITER). The International Thermonuclear Experimental Reactor is jointly supported by the European Community, the United States, and five other countries. Its construction cost has reached US$20 billion. (Reporter: Mao Li)

Indoor Ceiling Light

Indoor ceiling light are lighting fixtures installed on the ceiling of indoor spaces, typically consisting of one or multiple light bulbs and a lampshade or fixture. They can be used to illuminate living rooms, dining rooms, bedrooms, kitchens, hallways, and other indoor areas. Indoor ceiling light come in various designs and materials, and can be selected according to different decorative styles and needs. Some indoor ceiling light are also equipped with remote control or dimmers for better control of lighting brightness and color temperature.

Indoor Ceiling Light,Wood Ceiling Light,Indoor Ceiling Mount Lighting,Flush Mount Ceiling Light

Zhengdong Lighting Co., Ltd. , https://www.sundint.com