Why is the hydrogen bomb deployed by Yumin more powerful than that of the United States?

The T-U configuration of American hydrogen bombs is not as good as that of China.

20 14 National Science and Technology Awards Conference was held in Beijing. Academician Yu Min, a famous nuclear physicist in China and one of the outstanding leaders in nuclear weapons research and national defense high-tech development, won the highest national science and technology award in 20 14, and was the only scientist who won this honor.

Yu Min is a key figure in the research of H-bomb in New China. He solved a series of basic problems of China's breakthrough in the principle of hydrogen bomb, and put forward the idea that the principle and configuration are basically complete, which played a key role. 1965 10, because of Min's personal organization and deployment, the hydrogen bomb theory was broken. At present, there are only two hydrogen bomb configurations in the world, T-U configuration in the United States and Yu sensitive configuration in China. Since then, he has led the theoretical research and design of nuclear weapons for a long time and solved a lot of theoretical problems.

It has made important contributions to the further development of China's nuclear weapons to the international advanced level. Since 1970s, it has played an important role in advocating and promoting the research of some high-tech projects.

H-bomb blast

1982 won the first prize of National Natural Science Award. 1985, 1987 and 1989 won the national science and technology progress award three times. 1994 won the Outstanding Scientist Award of Qiushi Fund.

1999 was awarded the medal of "two bombs and one satellite" by the state. 1985 won the "May 1st Labor Medal". 1987 was awarded the title of "National Model Worker".

Due to the confidentiality of nuclear weapons, everything in Yu Min has been in a state of high secrecy for a long time. From 1976 to 1988, Yu Min's name is confidential. It was not until 1988 that Yu Min got the opportunity to go abroad for academic exchanges.

Because of work, Yu Min went abroad for the first time and visited the United States as a university professor. In less than a month, although he has been to many places, he has always been like a "mute": it is inconvenient to ask, it is inconvenient to say, and it is very uncomfortable.

Put forward the principle scheme of hydrogen bomb

Before the successful development of China's first atomic bomb, the relevant departments have made arrangements to require the theoretical exploration of hydrogen bombs to take the lead. At the end of 1960, Qian Sanqiang talked to Yu Min and asked him to participate in the research on the principle of hydrogen bomb. Yu did not hesitate to agree. Under the organization of Qian Sanqiang, a group of young scientists, mainly Yu Min, quietly started the theoretical exploration of hydrogen bomb technology. From atomic bomb to hydrogen bomb, according to the time comparison of breakthrough principle test, it took Americans 7 years and 3 months, Britain 4 years and 3 months, France 8 years and 6 months, and the former Soviet Union 4 years and 3 months.

One of the main reasons is the complexity of calculation. And China's equipment is even more incomparable. At that time, China had only one electron tube computer with ten thousand times per second, and 95% of the time was allocated to the calculation of atomic bombs, leaving only 5% of the time for the design of hydrogen bombs that Yu Min was responsible for.

China's first hydrogen bomb exploded successfully.

The poor have the way of the poor, and Yu Min's memory is amazing. The working group under his leadership has a slide rule and forgets to eat and sleep. Paper after paper was handed over to Qian Sanqiang, and unknown areas were conquered. Over the past four years, Yu Min, Huang Zuqia and other scientific and technological personnel have published 69 reports on research results, which have deeply understood many basic phenomena and laws of hydrogen bombs.

1In September, 964, 38-year-old Yu Min led a small team to Shanghai East China Computer Research Institute and worked hard to calculate several models. However, this model is bulky, with low power ratio and low fusion ratio, which does not meet the requirements. Yu Min summed up his experience, led scientific and technical personnel to calculate several models, found the key to self-sustaining combustion of thermonuclear materials, and solved the important topic of the principle scheme of hydrogen bomb. Yu Min said happily: "We caught the cow's nose!"

He immediately made an intriguing phone call to Deng Jiaxian in Beijing. In order to keep secret, Yu Min used a argot that only they could understand: it implied that there had been a breakthrough in the theoretical study of hydrogen bombs. "Several of us went hunting ... and caught a squirrel."

Deng Jiaxian heard the good news: "Did you have a delicious meal?" "No, it can't be cooked ... and become a specimen. ..... but we have a novel discovery. It has a special body structure and needs further anatomical research, but ... we are short of manpower. "

"Ok, I'll come to you right away." At the end of the same year, Yu Min began to engage in the theoretical research of nuclear weapons, put forward the idea that the principle and configuration of hydrogen bomb research are basically complete, solved a large number of key theoretical problems of thermonuclear weapons, and made remarkable achievements in the field of mean field independent particles.

Yu min

1967 June 17, China's first hydrogen bomb exploded successfully.

In the early 1980s, Yu Min realized the importance of inertial confinement fusion in national defense and energy. In order to attract everyone's attention, he made a report on "the current situation of laser fusion thermophysics research" in a certain range, and then organized and guided the development of nuclear theory research in China.

At the beginning of 1986, Deng Jiaxian and Yu Min made a profound analysis of the development trend of nuclear weapons science and technology in the world, and put forward suggestions to the central authorities to speed up China's nuclear test. Facts have proved that this proposal has played an important role in China's nuclear weapons development.

Recommended reading: The development of hydrogen bombs has to go through five thresholds.

At present, only the five permanent members of the United Nations Security Council are recognized as having mastered the hydrogen bomb technology. Less than two years after the third nuclear test, did North Korea really master this technology by three incomplete nuclear device tests? Let's see how many thresholds are usually needed for the development of hydrogen bombs.

Hydrogen bomb configuration is the primary difficulty.

The first is configuration theory. Hydrogen bomb technology matured in the 1960s. With the continuous disclosure of various related materials in the past 50 years, the principle of hydrogen bomb has been gradually exposed: at present, the only two hydrogen bomb configurations are Taylor-ulam configuration in the United States (t-u configuration for short) and sensitivity configuration in China, which are similar in essence, that is, hydrogen bombs include primary and secondary, and the primary one relies on X-rays emitted by fission energy to trigger the secondary fusion reaction. In this process, "how to achieve ignition conditions" is the core of hydrogen bomb configuration design; Therefore, the primary fission material is usually uranium or plutonium, and the secondary fusion material is usually deuterium, tritium or lithium deuteride.

However, even a preliminary understanding of the overall layout of the configuration is only the first step of the complete configuration design-because the configuration itself does not conform to physical intuition-in layman's terms, putting the secondary next to the atomic bomb should be that once the atomic bomb explodes, the secondary will be "blown" flat, and it is difficult to produce nuclear fusion.

Having said that, I have to mention a story. Many physics masters have stumbled on such physical intuition. For example, in the former Soviet Union, it was because there were many excellent mechanics experts that they intuitively thought that "this road was blocked" at the early stage of the development of hydrogen bombs. Taylor, the father of the American hydrogen bomb, is better. After calculation, he found that the secondary deformation limit was too high and needed to be protected. However, the protective sleeve would absorb energy so strongly that it could not be ignited, so he gave up the idea at first. It was not until Ulan mentioned this matter again later that Taylor suddenly found that he might have miscalculated one of the key details, so they recalculated it, so there was the so-called "Taylor-Ulan configuration".

The story sounds simple, but in fact, such a counterintuitive design not only uses the fission energy of the atomic bomb, but also ensures the secondary deformation. Obviously, it needs the perfect cooperation of other design and verification in many aspects-this involves two other barriers, "multidisciplinary cooperation" and "experimental verification".

"Discipline cooperation" and "experimental verification" are essential.

Let's talk about the second level, the problem of "multidisciplinary cooperation". The implication of the name "nuclear weapon" makes many people mistakenly think that nuclear bomb research is mainly nuclear physics research, but it is not. The central problem in the physical design of nuclear weapons is the coupling solution of radiation hydrodynamics equation and material characteristic equation (state equation, chemical and nuclear reaction equation, radiation free path problem, etc.). Around this core issue, more than ten categories and hundreds of sub-disciplines have been formed, including plasma physics, atomic and molecular physics, accelerator physics, condensed matter physics, explosive mechanics, thermodynamics, optics (high-speed photography and photonics, spectroscopy, laser physics, etc.). ), chemistry (radioactive chemistry, solid chemistry, nuclear chemistry, etc. ) and computer science (supercomputers, large-scale scientific computing methods, etc. These subjects are interwoven into an interdisciplinary network. Almost every key problem needs multidisciplinary cooperation. In order to establish so many disciplines in a country, each discipline has corresponding talents and needs a fairly strong basic national strength.

The difficulty in the coordinated development of disciplines is that the action process of nuclear weapons has the characteristics of instantaneity, high speed, high temperature, high density and high energy, and the research under such extreme conditions is often not a hot field of the above disciplines. Therefore, the accumulation of knowledge and parameters required for the theoretical design of nuclear weapons is difficult to obtain from public information and needs to be solved through special planning and special research by nuclear weapons research departments.

Next is the third level "experimental verification", that is, experimental sites and equipment that can reproduce these extreme conditions must be established to verify key parameters.

As mentioned above, the realization of a hydrogen bomb through an anti-physical sensing configuration requires fine cooperation in many aspects. In the final analysis, the design problem is still an engineering problem, and the key parameters need to be determined through experiments. This is also the reason why the United States and the Soviet Union are willing to spend huge sums of money to conduct thousands of thermonuclear tests. America's technology in this field is extremely advanced, and it was thought that in the future, nuclear tests could be simulated through massive test data and world-advanced supercomputers. However, in the past two years, there is still a gap in computer simulation ability between the aging research of its nuclear arsenal and the design of new nuclear weapons. In other words, nuclear testing is an inevitable link in the development of nuclear weapons.

As for the hydrogen bomb, no matter which country, it must go through the only way of "nuclear explosive device-weaponized atomic bomb-hydrogen bomb". The premise of secondary ignition of hydrogen bomb is that it must have enough equivalent and light weight at a time-this is the basic requirement of weaponization of atomic bomb. Moreover, all countries that make hydrogen bombs must first do an enhanced atomic bomb test, that is, put some deuterium-tritium mixture in the core of the atomic bomb to make it undergo a fusion reaction under the high temperature and high pressure of the atomic bomb explosion, and release a large number of neutrons, thus speeding up the fission reaction process of the fissile material wrapped around it and greatly improving the utilization efficiency of the fissile material. This is "fusion-assisted fission weapon". This kind of test is very necessary to verify the adjustment of equivalent calculation, fusion time and ignition temperature, and these technologies are just the premise of developing hydrogen bomb design.

Adequate nuclear materials and national strength are the foundation.

The fourth level of developing hydrogen bombs is to have enough nuclear materials. As the saying goes, a clever woman can't cook without rice. For hydrogen bombs, primary fission materials and secondary fusion materials are indispensable. The production of fissile material plutonium and fusion material tritium depends on reactors. According to the analysis of existing materials, foreign media speculated that it might be difficult for North Korea to produce enough fusion materials.

The last level is the issue of industrial capacity and economic capacity. Production of nuclear materials (uranium, plutonium, heavy water, deuterium, tritium, lithium, etc.). ) It needs a huge isotope factory, involving heavy industrial enterprises to produce key components for reactors, and the nuclear test itself also needs huge engineering construction (the underground nuclear test tunnel stretches for several kilometers and the depth reaches hundreds of meters underground), as well as complex, precise and huge nuclear test equipment. It can be said that the basis of nuclear weapons and their tests is a comprehensive test of a country's industrial capacity; If an image but not too strict estimate is given, it can be said that under the assumption that technical obstacles in various fields have disappeared, a small and medium-sized country may be able to conduct a hydrogen bomb test by putting all its industrial production capacity into operation for one year.

From the above analysis, we can see that to develop hydrogen bombs, we need to solve multiple technical, industrial and economic difficulties. For researchers in any country, it is entirely possible to make a breakthrough in hydrogen bomb configuration theory and multidisciplinary collaborative design. However, no one can be divorced from the law of nuclear weapons testing and actual production capacity. Under normal circumstances, it is impossible for a country to find another way to reach the other side of the successful hydrogen bomb test without enough tests, and it is also inseparable from the restrictions on the industrial capacity required for the production and testing of nuclear materials.

Vehicles are also a problem.

In addition to the development of the hydrogen bomb itself, any country that wants to develop nuclear weapons is also faced with the problem of means of delivery. If you want to use nuclear weapons, you must have a means of delivery, otherwise it is equivalent to having bullets and no guns. Traditionally, the means of delivery of strategic nuclear weapons such as hydrogen bombs mainly include aircraft and missiles. At present, it is mainly the latter means, especially ballistic missiles. However, there are still many problems to be solved to develop ballistic missiles using nuclear warheads.

First of all, we must complete the problem of miniaturization of nuclear bombs. The carrying capacity of ballistic missiles is limited. If a nuclear bomb cannot be miniaturized and lacks reliability (for example, it has to withstand launch vibration and tests outside the atmosphere), it cannot be used in ballistic missiles. The miniaturization of nuclear bombs also has obstacles for small and medium-sized countries. Some countries can break through the principle of nuclear weapons, but it is difficult to make practical nuclear weapons, which is closely related to this.

Second, we must break through the difficulty of reentry. The reentry stage of nuclear warhead refers to the process of nuclear warhead re-entering the atmosphere from the outside. In this process, the nuclear warhead quickly approaches the ground at a reentry speed of more than ten times the speed of sound, and the exterior of the projectile has to bear the high temperature caused by atmospheric friction. Whether the composite materials outside the missile can withstand this high temperature also puts forward high requirements for a country's R&D and manufacturing capabilities of composite materials. At the same time, the reentry phase also involves higher requirements such as strike accuracy and anti-missile defense.

In addition, the effectiveness and viability of the vehicle itself is also a problem. It is not difficult for a country to develop rockets and primary ballistic missiles, but it is difficult to develop high-performance missiles. Regardless of the performance of the missile itself, in terms of survivability, the solid mobile missile which is convenient for land maneuvering and long-term storage is obviously superior to the liquid mobile missile. Solid missiles have their own high and low technologies-to achieve the same carrying capacity, some countries can make short and lean models, while others cannot achieve the relative miniaturization of missiles.

In a word, the development of nuclear weapons and their means of delivery, including hydrogen bombs, is not a simple matter, and it has extremely high requirements for the country's comprehensive national strength, scientific and technological level and social organization structure. When analyzing international news, we can also refer to it from the technical level.