Share with friends and circles of friends with wechat scanning QR code < / P > < p > on November 16. At present, nuclear fusion reactors in the world are in the experimental stage. Recently, researchers used the high temperature and plasma inside the fusion reactor to simulate Jupiter's atmospheric environment, so as to test the heat shield used on spacecraft On December 7, 1995, a NASA probe entered Jupiter's atmosphere and immediately began to burn. The probe came from Galileo's Jupiter exploration mission, which began orbiting six months ago. The goal of going deep into Jupiter is to sample hydrogen and helium around the largest planet in the solar system < p > the spacecraft, called Jupiter atmospheric probe, is carefully designed so that its shell can withstand the soaring high temperature when it comes into contact with Jupiter's air. It has a huge carbon insulation layer, accounting for about 50% of the total weight of the detector. The design purpose is to dissipate heat through continuous wear during the descent of the detector. Scientists have carefully simulated this controlled process called ablation on earth. NASA even built a special test laboratory called giant planet facility < p > however, when the probe passes through Jupiter's atmosphere at a speed of nearly 200000 kilometers per hour, friction heats the air around it to 15000 degrees Celsius. At this high temperature, atoms split into charged particles and produce a hot plasma called plasma. Natural phenomena such as lightning or aurora on earth originate from plasma, and the sun itself is also a huge plasma. It is often called the fourth state of matter, but it is actually the first state. At the moment after the big bang, plasma was the only substance < p > the plasma engulfed the Jupiter probe's heat shield much faster than NASA expected. After NASA engineers analyzed the sensor data embedded in the heat shield, they realized that their carefully designed model deviated from the goal. The decomposition of the heat shield is much faster in some areas and slower in some parts. The only reason why the detector survived was that engineers thickened the heat shield in the design to make room for errors. "This issue remains unresolved," said EVA kostadinova, a plasma expert at Auburn University. "But if you want to design a new mission, you must be able to correctly simulate what is happening." < / P > < p > after Galileo's Jupiter exploration mission, scientists used the probe data to adjust the ablation model, but still face a big problem: it is very difficult to accurately reproduce the conditions of entering Jupiter's dense atmosphere at high speed, Therefore, it is difficult to test these models accurately. This also poses an obstacle to the manufacture of new insulation materials that are lighter and better than the carbon based materials currently used. If new materials cannot be tested, it is difficult to be sure that they will work on multi billion dollar spacecraft < p > the usual tests use laser, plasma jet and high-speed projectile to simulate the heat when the detector enters the atmosphere, but none of them is completely correct. Costadinova said, "no space facility on earth can reach the high temperature conditions experienced when entering Jupiter's atmosphere." < / P > < p > now, costadinova and Dimitri Orlov from the University of California, San Diego have conducted a new study, The hot high temperature inside the experimental nuclear fusion reactor is used to test the thermal insulation materials of spacecraft < p > among the research facilities funded around the world, there are hundreds of controlled nuclear fusion reactors called Tokamak, including the joint European torus in the UK and the International Thermonuclear Experimental Reactor in southern France (ITER). For decades, researchers have been using them to study how to use nuclear fusion to provide virtually unlimited energy. In the Tokamak, strong magnets under high pressure are used to restrain the high-speed rotating plasma to reach the tens of millions of degrees of temperature required for atomic fusion and energy release. Some critics believe that nuclear fusion is doomed to be impossible. Now nuclear fusion experiments More electricity is consumed than generated. < / P > < p > but costadinova and Orlov are more interested in the plasma in these reactors. They realize that this may be the perfect environment to simulate the spacecraft entering Jupiter's atmosphere. Orlov studied Aerospace Engineering and is currently working at the U.S. Department of energy's DIII-D fusion reactor in San Diego. < / P > < p > They conducted a series of ablation experiments using DIII-D equipment. They used a port at the bottom of the Tokamak equipment to insert a series of carbon rods into the plasma stream, and used high-speed infrared cameras and spectrometers to track how they were decomposed. Orlov and costadinova also fired miniature carbon balls at high speed to simulate the Galileo detector The small-scale thermal shielding that may be encountered in Jupiter's atmosphere. < / P > < p > the internal conditions of tokamak are very similar in terms of plasma temperature, the speed of plasma flowing on the material surface, and even the specific composition of plasma: the main components of Jupiter's atmosphere are hydrogen and helium, and the DIII-D fusion reactor uses deuterium, an isotope of hydrogen. Orlov said: "Instead of launching an object at high speed, we put a stationary object into a very fast fluid." < / P > < p > these experiments were held at the American Physical Society this month It was announced at the American Physical Society meeting, which helps to verify the ablation model developed by NASA scientists using the data of Galileo Jupiter probe, and can also be used as a proof of concept for new material testing. "We are opening up new research fields," Orlov said. "No one has done this before." < / P > < p > "This is what the industry needs very much. New material testing procedures often lag behind," said Yanni barghouty, founder of cosmoic shielding, a start-up that makes radiation shields for spacecraft. "It allows you to develop prototypes faster and cheaper. It's a feedback system." < / P > < p > it remains to be seen whether nuclear fusion reactors can become test sites for practical applications. After all, these nuclear fusion devices are extremely sensitive equipment designed for another purpose. Orlov and costadinova's research using the built-in port of Tokamak to safely test new materials is part of many ways to expand scientific knowledge by using reactors, but the cost is high. He said They spent $500000 a day experimenting on the machine ?
2023-03-22 10:04:46