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A laser that promotes high energy density physics

Release time:2018-03-20

When the pressure is 1 million times or 1 billion times more than the earth's atmospheric pressure, the performance of the atom is very different. Understanding the response of atoms to such a high pressure condition can lead to the production of new materials, and enable scientists to provide valuable insights into the composition of stars and planets and the universe itself.

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This is one of the reasons why University of Rochester has shifted its attention to the relatively new field of high-energy density physics. Another reason is that the university is preparing to make a significant contribution to the field.


Rob Clark, vice president and Research Department of University of Rochester, said: "our researchers and our resources make us uniquely positioned to get important insights in the field of high-energy density physics.


And the Laser Dynamics Laboratory of University of Rochester is the location of the OMEGA laser. The 10 - meter - high, 100 - meter - long OMEGA is the world's largest university - based laser.

Rochester also specially hired Gilbert (Rip) Collins to lead the new multidisciplinary research program in the field of high-energy density physics. Collins used to be the director of high energy density physics center of Lawrence Livermore National Laboratory. He is now a professor in the Department of mechanical engineering / Physics and astronomy, and also a senior scientist in the laser energy laboratory of the University. "This study will make the collaboration between chemistry, engineering, physics and astronomy easier", Collins points out, so that progress in this field will be accelerated.


In addition to other studies, Collins also studied the bonding of atoms under extreme pressure. In general, the outermost electron of an atom reacts with the electrons of other atoms. However, when the pressure exerted on the atom is greatly increased, the internal electrons will intervene, and there will be an interesting phenomenon.


"Under extreme pressure," Collins points out, "the chemical properties of the elements we are familiar with are no longer applicable. For different pressure conditions, we need a new periodic table of elements. A diamond is a well known material under high pressure. " Placing carbon on the earth 100 miles deep, the pressure is 50000 times higher than the earth's surface pressure, and the temperature is higher than 2000 degrees Fahrenheit. Its atomic structure will become very coherent. We call it diamond.


However, when the physics of high-energy density is involved, the pressure level is still low. Under more extreme pressure, for example, 2 million atmospheres, sodium can be transformed into insulators. Under 10 million atmospheric pressure, hydrogen becomes superconducting superfluid, and when pressure exceeds 200 million atmospheres, aluminum can be transparent.


The above OMEGA laser can enable researchers to achieve this pressure condition.

"A lot of people think that lasers are just a heat source," Collins said. Little by little, lasers can also serve as a highly concentrated source of pressure. OMEGA lasers enable us to study materials under millions to billions of atmospheres. Understanding the behavior of atoms under extreme pressure will enable researchers to purposefully deal with matter and form new, uncommon materials. "


Robert McCrory, vice president and director of the laser energy laboratory, said that Collins has a high international reputation and is very suitable for leading the University's project. He pointed out that laser labs, Lawrence Livermore's National Ignition facilities and other facilities have opened up new frontiers of high-energy density physics, and have ensured the leading position of the United States in this field.


High energy density physics can provide more for the creation of new materials. Michael Campbell, the deputy director of the laser energy laboratory, called the field "persistent science."


He pointed out: "there will always be new fields to explore, including the nature of the universe itself. The pressure of the center of a planet is over millions of times more than the atmospheric pressure, and the pressure of the stars is billions of times the atmospheric pressure. High energy density physics can help us understand how planets and stars are generated, such as the earth has magnetic field, and the radiation and energy flow in the sun and other stars.