The studies carried out in the period 2001-2014 are described. with the participation of Russian and German scientists and cosmonauts, research of plasma crystals on the International Space Station. During the experiments, a number of new effects and phenomena were discovered that were not observed under the conditions of Earth's gravity and expanded our understanding of the structure and dynamics of matter.
For specialists in the physics of dusty plasma, as well as everyone who is interested in the issues of setting up a modern space experiment, organization and practice of space research.
REFERENCE POINT.
Scientific research in space is a complex undertaking. From conception to full implementation, a project can last more than twenty years. This means that researchers must be quite young or that they may have to transfer their knowledge and skills and delegate their experimental responsibilities to junior colleagues.
Space research can be different - there can be research from space (for example, remote sensing of the Earth or astronomy), research into space itself (for example, the study of near-Earth space, space weather, the study of the interplanetary medium, as well as individual planets, the Moon, asteroids and comets) and more research using specific features space (let's say, weightlessness, more precisely, microgravity and huge distances). Some research is more convenient to carry out on unmanned spacecraft with the help of automatic machines and robotics, while others require experiments carried out by people - similar to those carried out in earthly scientific laboratories.
CONTENT
From the authors
1. Starting point
2. "Plasma Crystal"
3. We need a space experiment
4. Crystallization of Russian-German cooperation
5. Germany: experiment in parabolic flight
6. Germany: rocket experiment
7. Russia: the first Plasma Crystal experiment in space
8. How the international space station was born
9. Russian-German plan
10. Farewell to “Mir”
11. Creation of an experimental setup
12. Baikonur Cosmodrome
13. Experiment "PK-3"
14. Cosmonaut Training Center
15. Korolev - space city
16. Experiment “PK-3+”
17. “Plasma crystal” in the constellation of astronauts
18. Our meetings on Earth
19. Research results
20. The future is here
21. Final word
Bibliography.
Free download e-book at convenient format, watch and read:
Download the book Plasma crystal, Space experiments, Fortov V.E., Baturin Yu.M., Morfill G.O., Petrov O.F., 2015 - fileskachat.com, fast and free download.
Sakharova T.A. (n-Kislyay settlement, MKOU Nizhnekislyayskaya secondary school named after Polyakov)
1. Artsimovich L.A. "Elementary Plasma Physics".
2. http://www.nkj.ru/archive/articles/1318/ (Science and life, CRYSTALS IN DUSTY PLASMA).
3. Robert L. Merlino. Experimental Investigations of Dusty Plasmas (English) (PDF). Department of Physics and Astronomy, The University of Iowa (17 June 2005). – Historical review of dusty plasma research. Retrieved July 18, 2009. Archived from the original on April 2, 2012.
4. Fortov V.E., A.G. Khrapak, S.A. Khrapak, V.I. Molotkov, O.F. Petrov. Dusty plasma (Russian) // UFN. – 2004. – T. 174. – P. 495–544.
5. Tsytovich V.N. Plasma-dust crystals, drops and clouds (Russian) // UFN. – 1997. – T. 167. – P. 57–99.
6. Dusty plasma // Encyclopedia of low-temperature plasma. – M.: Janus-K, 2006. – T. 1.
7. Fortov V.E. Plasma-dust crystals and liquids on Earth and in Space (Russian) // Vestnik Russian Academy Sci. – 2005. – T. 75, No. 11. – P. 1012-1027.
8. Klumov B.A. On the melting criteria of complex plasma (Russian) // UFN. – 2010. – T. 180. – P. 1095–1108.
9. Video from YouTube “Studying field crystals in space.”
Plasma is the most common state of matter in nature: it is estimated that approximately 95% of ordinary matter in the Universe is in this state. Stars are clumps of plasma, ionized gas with temperatures of tens and hundreds of millions of degrees. The properties of plasma form the basis of modern technologies, the scope of which is extensive.
I took up this research work because I was interested in the fourth state of matter, which is still little studied in the modern world - plasma. I was fascinated by a phenomenon recently discovered in low-temperature plasma - the formation of a “plasma crystal”, that is, a spatially ordered structure of fine particles - plasma dust.
Target my research: obtaining low-temperature plasma through experiment, getting acquainted with plasma field crystals.
Research objectives:
1. Expand knowledge about “plasma”.
2. Get low-temperature plasma at home.
3. Find out the areas of application of plasma.
4. Conduct an analysis of information obtained from various sources and experimental data.
The relevance of this work is that in lately Plasma physics is an actively developing field of science, in which amazing discoveries are being made to this day, unusual phenomena are observed that require understanding and explanation. Discoveries in this area will improve the quality of human life: organize waste recycling; production of alternative energy; microchip production; increasing the strength of metals; invention of new plasma engines; defeat harmful microbes; improve the quality of color images in plasma panels; explain the evolution of the Universe, etc.
Working with information sources
History of the discovery of plasma
The fourth state of matter was discovered by W. Crookes (Fig. 1) in 1879 and called “plasma” by I. Langmuir (Fig. 2) in 1928, possibly due to associations with the fourth state of matter (plasma) with blood plasma.
Rice. 1. W. Krugson
Rice. 2. I. Langmuir
I. Langmuir wrote: “Excluding the space near the electrodes, where a small number of electrons is found, an ionized gas contains electrons and ions in almost equal quantities, as a result of which the total charge of the system is very small. "We use the term 'plasma' to describe this generally electrically neutral region of ions and electrons." .
Plasma concept
Plasma is a partially or fully ionized gas formed from neutral atoms (or molecules) and charged particles (ions and electrons). The most important feature of plasma is its quasineutrality, which means that the volume densities of positive and negative charged particles from which it is formed are almost the same.
A gas turns into a plasma state if some of its constituent atoms (molecules) for some reason have lost one or more electrons, i.e. turned into positive ions. In some cases, negative ions can also appear in the plasma as a result of the “attachment” of electrons to neutral atoms.
If there are no neutral particles left in the gas, the plasma is said to be fully ionized. Plasma obeys gas laws and behaves like a gas in many respects. At the same time, the behavior of plasma in a number of cases, especially when exposed to electric and magnetic fields, turns out to be so unusual that it is often referred to as a new fourth state of matter (Fig. 3).
Rice. 3. The fourth state of matter
What's happened dust plasma?
Dusty plasma is an ionized gas containing dust grains - particles of solid matter. Such plasma is often found in space: in planetary rings, comet tails, interplanetary and interstellar clouds (Fig. 4). It was discovered near artificial Earth satellites and in the near-wall region of thermonuclear installations with magnetic confinement, as well as in plasma reactors, arcs, and discharges.
Rice. 4. Plasma comet tail
Dust plasma was first obtained in laboratory conditions by the American Irving Langmuir back in the 20s of the last century. However, it began to be actively studied only in the last decade. Increased interest in the properties of dusty plasma arose with the development of technologies for plasma sputtering (Fig. 5) and etching in microelectronics (Fig. 6), as well as the production of thin films (Fig. 7) and nanoparticles (Fig. 8).
Rice. 5. Plasma spraying
Fig.6. Etching platinum in hydrogen
Rice. 7. Thin semiconductor film
Fig.8. Nanoparticles
Plasma crystal
The sizes of dust particles are relatively large - from fractions of a micron to several tens, sometimes hundreds of microns (Fig. 9). Their charge can be extremely large and exceed the charge of an electron by hundreds and even hundreds of thousands of times. As a result, the average Coulomb interaction energy of particles, proportional to the square of the charge, can greatly exceed their average thermal energy (Fig. 10). The result is a plasma that is called highly nonideal, since its behavior does not obey the laws of an ideal gas. (Recall that plasma can be considered an ideal gas if the interaction energy of particles is much less than their thermal energy).
Rice. 9. Plasma Crystal
Rice. 10. Coulomb interaction
Theoretical calculations of the equilibrium properties of dusty plasma show that, under certain conditions, strong electrostatic interaction “takes over” low thermal energy and forces charged particles to line up in space in a certain way. An ordered structure is formed, which is called a Coulomb or plasma crystal. Plasma crystals are similar to spatial structures in a liquid or solid (Fig. 11). Phase transitions such as melting and evaporation can occur here.
Rice. 11. Plasma crystal
If the dust plasma particles are large enough, the plasma crystal can be observed with the naked eye.
Obtaining low-temperature plasma at home
After some research into the properties and characteristics of plasma, I was able to conduct an experiment in producing low-temperature plasma at home (Video “Producing Plasma”). To do this, I needed the following equipment: microwave oven, windproof match, glass jar.
Rice. 12. Preparatory stage
Progress of the experiment:
1. First, I removed the glass dish from the microwave oven on which the food rotates when heated. Prepared a match (Fig. 12).
2. Then I inserted a match into the center of the Microwave and lit it.
3. After that, I covered the match with a glass jar, then closed the microwave oven, turned it on, setting the food heating function (Fig. 13).
4. After a certain amount of time, you can see how plasma is formed in a glass jar with a lit match (Fig. 14).
Rice. 13. Match under a glass jar in a microwave oven
Rice. 14. Low temperature plasma
Thanks to this simple experience you can see how the gas is ionized under the influence of temperature and thereby obtains a partially ionized plasma. If I was able to obtain low-temperature plasma so easily, then it can be obtained at enterprises, while the costs of obtaining it are minimal.
Conclusions
I managed to obtain low-temperature plasma at home. I expanded my knowledge on this issue and learned a lot of new and interesting things. I was very interested in this topic and I am sure that when I choose a profession, this research work will leave its mark.
"Chaotic" plasma is the 5th state of matter. Crystalline plasma is a state of "organized" plasma where it does not need to be contained by a magnetic field. The properties of plasma form the basis of modern technologies, the scope of which is extensive.
I believe that plasma is a symbol of the future, the most important industry, without which it is unthinkable further development civilization. Plasma, in my opinion, is an alternative source of energy and a doctor of ecology.
Dusty plasma is an ionized gas containing particles of condensed matter. Other terms used to designate such systems are “complex plasma”, “colloidal plasma”, and also “plasma with a condensed dispersed phase”. Dust and dusty plasma are widespread in space. They are present in planetary rings, comet tails, and interplanetary and interstellar clouds. Dust plasma discovered near artificial earth satellites and spacecraft, in thermonuclear installations with magnetic confinement. Finally, dusty plasma is being very actively studied in laboratory conditions. Dust particles can not only be deliberately introduced into the plasma, but also form spontaneously as a result of various processes. Widespread occurrence of plasma-dust systems, as well as a number of unique properties, make dusty plasma an extremely attractive and interesting object of study.
Dust particles in the plasma acquire an electrical charge and represent an additional charged component of the plasma. However, the properties of dusty plasma are much richer than the properties of multicomponent plasma of electrons and ions different varieties. Dust particles are centers of recombination of plasma electrons and ions and, sometimes, a source of electrons. Thus, the dust component can significantly affect the ionization equilibrium. The charge of dust particles is not a fixed value, but is determined by the parameters of the surrounding plasma and can vary both in time and space. In addition, the charge fluctuates even with constant parameters of the surrounding plasma, since charging is a stochastic process.
Dust plasma particles can line up in space in a certain way and form a so-called plasma crystal. The plasma crystal can melt and evaporate. If the dust plasma particles are large enough, the crystal can be seen with the naked eye.
The building material for dust crystals are macroparticles, the size of which can vary up to tens of microns depending on the conditions of a particular experiment. The lattice constant in such crystals usually significantly exceeds the Debye screening radius and can reach hundreds of microns. In addition to the formation of crystalline dust structures in plasma in many cases, plasma-dust droplets have been detected, and gas-liquid phase transitions in such systems have been observed.
The charge of dust particles can be extremely large and exceed the charge of an electron by hundreds and even hundreds of thousands of times. As a result, the average Coulomb interaction energy of particles, proportional to the square of the charge, can greatly exceed their average thermal energy. The result is a plasma that is called highly imperfect, since its behavior does not obey the laws of an ideal gas. (Recall that plasma can be considered an ideal gas if the interaction energy of particles is much less than their thermal energy).
Plasma crystals are similar to spatial structures in a liquid or solid. Phase transitions such as melting and evaporation can occur here.
If the dust plasma particles are large enough, the plasma crystal can be observed with the naked eye. The formation of crystalline structures was recorded in a system of micron-sized charged particles of iron and aluminum held by alternating and static electric fields. Coulomb crystallization of macroparticles in weakly ionized plasma of a high-frequency discharge at low pressure. The energy of electrons in such a plasma is several electronvolts (eV), and the energy of ions is close to the thermal energy of atoms, which are at room temperature (~ 0.03 eV). This is due to the fact that electrons are more mobile and their flux directed at a neutral dust particle significantly exceeds the flux of ions. The particle “catches” electrons and begins to charge negatively. This accumulated negative charge in turn causes electrons to repel and ions to attract. The particle's charge changes until the fluxes of electrons and ions on its surface become equal. With a high-frequency discharge, the charge of dust particles will increase and will be negative. A cloud of charged dust particles hovered near the surface of the lower electrode as an equilibrium between gravitational and electrostatic forces was established there. With a cloud diameter of several centimeters in the vertical direction, the number of particle layers was several tens of micrometers.
The legendary experiment, which began at the Soviet orbital station Mir, was continued on the ISS with new equipment. A unique device that was recently delivered on board the space station is an additional gas flow regulator device. It will make it possible to obtain more accurate results during an experiment studying plasma and will increase its purity. Data about what dusty plasma is will make it possible to obtain previously unknown information about the Universe, create compact energy batteries and lasers, and develop new technology cultivation of diamonds, and also serve as the basis for the development of plasma medicine.
Any substance can exist in four phase states - solid, liquid, gaseous and plasma. Plasma makes up more than 99% of the visible mass of the Universe, from stars to interstellar gas. Plasma containing dust particles is very common in space - these are planetary rings, comet tails, interstellar clouds.
The study of plasma with microparticles several microns in size (dust particles) and observation of its behavior in microgravity conditions, in which almost complete compensation of the weight of microparticles occurs, has been going on for more than two decades. Back in January 1998, at the Russian Mir orbital complex, cosmonauts Anatoly Solovyov and Pavel Vinogradov conducted the first experiment on the Plasma Crystal-1 (PK-1) installation to study the physics of plasma-dust structures, including plasma crystals and liquids. In August of the same year, Mir began conducting research using PK-2 equipment, consisting of a gas-discharge tube and a device for video recording the experiment. In March 2001, Sergei Krikalev and Yuri Gidzenko conducted the first session of the experiment on the ISS using the PK-3 installation, created jointly by Russian and German specialists. First experiments on the new installation "Plasma Crystal-4", also created jointly by scientists from the United Institute high temperatures(JIHT) RAS and the German Space Agency (DLR), began in June 2015. During the research process, the need to improve this installation was identified. In July of this year, additional equipment was delivered to the ISS to improve the quality of the Plasma Crystal-4 experiment.
The goal of scientists is to obtain and study plasma-dust crystals and other ordered structures in plasma. In particular, this makes it possible to study the laws of processes occurring in protostars, protoplanetary rings and other celestial bodies. During the experiments, microscopic particles of a certain size (several micrometers in diameter) are introduced into a neon or argon plasma in a gas discharge tube. When microparticles enter the plasma, they collect electrons and positive ions, resulting in a negative charge due to higher electron mobility. Microparticles repel each other and form various three-dimensional structures. Such studies cannot be carried out on Earth, since dust particles are subject to gravity and can form either two-dimensional structures or highly deformed (compressed) three-dimensional ones.
Despite the fact that over the twenty-year history of dusty plasma research has yielded a lot of new interesting data, it has not yet been possible to create a complete mathematical model of the behavior of self-organizing particles. New equipment developed by scientists from the Joint Institute for High Temperatures of the Russian Academy of Sciences and DLR will allow for cleaner experiments by reducing the gas flow that forms the plasma by tens of times. Now it is possible to expand the range of gas pressures and obtain new knowledge about processes in dusty plasma.
When microparticles are in plasma, they are subject to a number of forces. One of the main ones is electrical, affecting the particle in the discharge field. The second is the force of ion entrainment. The third is friction with gas: if a body enters the atmosphere, then it loses speed precisely because of it, Andrei Lipaev, a senior researcher at the Joint Institute for High Temperatures of the Russian Academy of Sciences, told Izvestia. - Accordingly, when we organize a flow mode, a kind of wind arises that carries away the particles. The device, which was originally used to block the flow, during operation in the difficult conditions of the space experiment began to produce a significant gas leak, and the particles were simply carried away by the flow.
To solve this problem, specialists from JIHT RAS and DLR have developed an additional device that allows you to fully control the gas flow using an external pressure regulator and two additional valves. In this way, a stable position of the particles can be achieved. As a result, scientists had the opportunity to fully control the experimental conditions.
We can say that until now we simply could not get necessary control above the gas flow and therefore quality results. Previously, it was simply impossible to work with particles smaller than 3 microns. Meanwhile, it is particles about 1 micron in size that are interesting from the point of view of studying processes such as, for example, the formation of structures, noted Andrey Lipaev.
New equipment has already been installed on the ISS, and the image is transmitted from board to the Mission Control Center. Employees of the Joint Institute for High Temperatures of the Russian Academy of Sciences receive telemetry and video of the experiment, and audio communication channels with the ISS board are also working - you can hear how negotiations are taking place. A new multi-day experiment using additional equipment to study dust particles in plasma was recently completed and lived up to expectations. Now scientists will conduct a detailed analysis of its results.
As Oleg Petrov, director of the Joint Institute for High Temperatures of the Russian Academy of Sciences, told Izvestia, the data obtained during the experiment will help to understand the essence of self-organization processes.
The system we are studying is an open dissipative system: there is a constant influx of energy and a constant outflow. Such systems are characteristic of all living organisms. What is happening to this system, what phenomena of self-organization are there in it? All this can and should be explored,” noted Oleg Petrov.
Data about what constitutes dusty plasma can be of great practical benefit: they will allow, in particular, to create new compact energy batteries and lasers and develop technology for growing diamonds in microgravity conditions. Also, data coming from on board the ISS is important for the development of plasma medicine, the essence of which is that low-temperature plasma can initiate, stimulate and control complex biochemical processes in living systems.
The PK-4 experiment is carried out with the support of Roscosmos and the European Space Agency.
