“plasma”的概念、定义、翻译、参考文献-科学参考

plasma

Physics

A highly ionized gas in which the number of free electrons is approximately equal to the number of positive ions. Sometimes described as the fourth state of matter, plasmas occur in interstellar space, in the atmospheres of stars (including the sun), in discharge tubes, and in experimental thermonuclear reactors.

Because the particles in a plasma are charged, its behaviour differs in some respects from that of a gas. Plasmas can be created in the laboratory by heating a low-pressure gas until the mean kinetic energy of the gas particles is comparable to the ionization potential of the gas atoms or molecules. At very high temperatures, from about 50 000 K upwards, collisions between gas particles cause cascading ionization of the gas. However, in some cases, such as a fluorescent lamp, the temperature remains quite low as the plasma particles are continually colliding with the walls of the container, causing cooling and recombination. In such cases ionization is only partial and requires a large energy input. In thermonuclear reactors an enormous plasma temperature is maintained by confining the plasma away from the container walls using electromagnetic fields (see pinch effect). The study of plasmas is known as plasma physics.

Astronomy

A state of matter consisting of ions and electrons moving freely. Stars consist of plasma, and plasmas exist in interstellar space; the solar wind is a plasma. Because a plasma is highly ionized, its behaviour differs from that of a normal gas. External magnetic and electric fields can affect a plasma, and the charged particles themselves can interact magnetically and electrically.

Space Exploration

The ionized gas produced at extremely high temperatures, as in the Sun and other stars. It contains positive and negative charges in equal numbers. It is a good electrical conductor. In thermonuclear reactions the plasma produced is confined through the use of magnetic fields.
http://www.plasmas.org/ Impressive guide to plasmas. The site has lots of good articles on plasma basics, plasma technology, and the applications of plasma science. The pages contain lots of photographs, and there is a gallery of colourful and interesting plasma pictures.

Chemical Engineering

1. A state of matter resulting from the ionization of gases in which the number of positive and negative ions is approximately the same. In a thermonuclear reactor, a very high temperature is maintained by retaining the plasma away from the walls using strong electromagnetic fields. It was first identified in 1879 and the nature of the matter was then identified by British scientist Sir Joseph John Thomson (1856–1940) in 1897. Irving Langmuir first used the term plasma in 1928.

2. The colourless part of blood in which corpuscles are suspended.

Electronics and Electrical Engineering

1. A region of ionized gas in an arc-discharge tube (see gas-discharge tube) that contains approximately equal numbers of electrons and positive ions and provides a conducting path for the arc discharge.
2. (positive glow) See gas-discharge tube.
3. A fully ionized gas in which electrons and ions move freely, with electric and magnetic fields affecting and arising from the moving charged particles. A plasma can be formed at high temperatures, as in stars and experimental thermonuclear reactors, or by photoionization.

Biology

See blood plasma.

Geology and Earth Sciences

A low-density, high-temperature, completely ionized gas, consisting of free atomic nuclei and free electrons. Overall it is electrically neutral. It is sometimes referred to as the ‘fourth state of matter’.

单词	plasma
释义	plasma Physics A highly ionized gas in which the number of free electrons is approximately equal to the number of positive ions. Sometimes described as the fourth state of matter, plasmas occur in interstellar space, in the atmospheres of stars (including the sun), in discharge tubes, and in experimental thermonuclear reactors. Because the particles in a plasma are charged, its behaviour differs in some respects from that of a gas. Plasmas can be created in the laboratory by heating a low-pressure gas until the mean kinetic energy of the gas particles is comparable to the ionization potential of the gas atoms or molecules. At very high temperatures, from about 50 000 K upwards, collisions between gas particles cause cascading ionization of the gas. However, in some cases, such as a fluorescent lamp, the temperature remains quite low as the plasma particles are continually colliding with the walls of the container, causing cooling and recombination. In such cases ionization is only partial and requires a large energy input. In thermonuclear reactors an enormous plasma temperature is maintained by confining the plasma away from the container walls using electromagnetic fields (see pinch effect). The study of plasmas is known as plasma physics. Astronomy A state of matter consisting of ions and electrons moving freely. Stars consist of plasma, and plasmas exist in interstellar space; the solar wind is a plasma. Because a plasma is highly ionized, its behaviour differs from that of a normal gas. External magnetic and electric fields can affect a plasma, and the charged particles themselves can interact magnetically and electrically. Space Exploration The ionized gas produced at extremely high temperatures, as in the Sun and other stars. It contains positive and negative charges in equal numbers. It is a good electrical conductor. In thermonuclear reactions the plasma produced is confined through the use of magnetic fields. http://www.plasmas.org/ Impressive guide to plasmas. The site has lots of good articles on plasma basics, plasma technology, and the applications of plasma science. The pages contain lots of photographs, and there is a gallery of colourful and interesting plasma pictures. Chemical Engineering 1. A state of matter resulting from the ionization of gases in which the number of positive and negative ions is approximately the same. In a thermonuclear reactor, a very high temperature is maintained by retaining the plasma away from the walls using strong electromagnetic fields. It was first identified in 1879 and the nature of the matter was then identified by British scientist Sir Joseph John Thomson (1856–1940) in 1897. Irving Langmuir first used the term plasma in 1928. 2. The colourless part of blood in which corpuscles are suspended. Electronics and Electrical Engineering 1. A region of ionized gas in an arc-discharge tube (see gas-discharge tube) that contains approximately equal numbers of electrons and positive ions and provides a conducting path for the arc discharge. 2. (positive glow) See gas-discharge tube. 3. A fully ionized gas in which electrons and ions move freely, with electric and magnetic fields affecting and arising from the moving charged particles. A plasma can be formed at high temperatures, as in stars and experimental thermonuclear reactors, or by photoionization. Biology See blood plasma. Geology and Earth Sciences A low-density, high-temperature, completely ionized gas, consisting of free atomic nuclei and free electrons. Overall it is electrically neutral. It is sometimes referred to as the ‘fourth state of matter’.
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