Plasma state

The plasma state is often referred to as tire fourtli state of matter [1]. It is characterized by tire presence of free positive (and sometimes also negative) ions and negatively charged electrons in a neutral background gas. The... 

Plasma can be broadly defined as a state of matter in which a significant number of the atoms and/or molecules are electrically charged or ionized. The generally accepted definition is limited to situations whereia the numbers of negative and positive charges are equal, and thus the overall charge of the plasma is neutral. This limitation on charge leaves a fairly extensive subject area. The vast majority of matter ia the universe exists ia the plasma state. Interstellar space, interplanetary space, and even the stars themselves are plasmas. 

There are some other states of matter, although we don t normally encounter them. The best known is plasma. In the plasma state, the electrons have been stripped from the atoms, leaving free electrons and bare nuclei (see chapter 1 for an explanation of atoms and electrons). A plasma can be formed either by heating a gas to a very high temperature or by passing an electric current through a gas.The sun forms plasma naturally. 

Therefore, by adding enough energy to any material, we can eventually dissociate it into atomic nuclei and electrons, hence turning it into a plasma. Our own Sun, unlike the Earth and the other planets, is in this plasma state, as are all stars. Although plasmas on Earth are artificial, the greater part of the visible Universe is made up of plasmas. 

The fact that the Sun is in the plasma state means that it has the flexibility of a gas. This flexibility in turn ensures its longevity. Indeed, the size of the particles making it up, i.e. separate nuclei and electrons, is much less than the mean distance separating them, and this allows us to identify it with a gas. (Non-baryonic dark matter, with no electrical properties, cannot be ionised. There is no such thing as a dark matter plasma.)... 

Plasma state of matter in which atoms or molecules have been ionized to form positive ions and electrons Plasmolysis condition that results when cells absorb water and rupture Pneumatic Chemistry study of gases and air, important in the development of modern chemistry... 

The fourth state of matter, the plasma state , although rarely found at the surface of the earth, is the most commonly found state of matter when the known universe is considered. The plasma state, consisting of a neutral collection of electrons and positive ions, may have a very wide range of densities. The production and properties of this state are described. 

Plasma Plasma is a gas-like state in which electrons pop off gaseous atoms to produce a mixture of free electrons and cations (atoms or molecules with positive charge). For most types of matter, achieving the plasma state requires very high temperatures, very low pressures, or both. Matter at the surface of the sun, for example, exists as plasma. 

The plasma state can be created by a variety of means. In general, when a molecule is subjected to a severe condition, such as intense heat, ionization of the molecule takes place. At temperatures higher than 10,000 K, all molecules and atoms tend to become ionized. The sun and other stars of the universe have temperatures ranging from 5,000 to 70,000 or more, so they consist entirely of plasma. 

In a laboratory environment, plasma is generated by combustion, flames, electric discharge, controlled nuclear reactions, shocks etc. Because a plasma loses energy to its environment mainly by radiation and conduction to walls, the energy must be supplied as fast as it is lost in order to maintain the plasma state. Of the various means of maintaining the plasma state continuously for a relatively long period of... 

To reach the plasma state of atoms and molecules, energy for the ionization must be absorbed by the atoms and molecules from an external energy source. Furthermore, the plasma state does not continue at atmospheric pressure, but at a low pressure of... 

Torr. The essential items for plasma generation are (1) an energy source for the ionization (2) a vacuum system for maintaining the plasma state and (3) a reaction chamber. 

This chapter aims to discuss and summarize theoretical and practical aspects of such plasma interfaces, presenting the existing examples from our own recent work on plasma electrochemical reactions between typical ionic liquids and plasmas. First, we address the plasma state and essential properties with respect to its application in electrochemistry. Today, low temperature plasmas - mostly in the form of radiofrequency or microwave plasmas - play an important role in the treatment or modification of solid surfaces. However, as plasma chemistry is usually not an element of chemistry curricula, we include a very brief introduction but refer the reader to the literature for more detailed information. 

Plasma electrochemical reactions have been studied by chemists for a surprisingly long time, with the first report on cathodic metal deposition at the free surface of a liquid electrolyte with free electrons from a plasma dating back to 1887 [1], long before the plasma state had been named by Langmuir in 1928 [2], A short survey of past work with more conventional liquid electrolytes is also included in this chapter. 

Fig. 2.9. Divertor plasma pressure profiles. Clearly visible strong pressure drop in front of inner target in the left (case 1) figure, indicative of a detached plasma state there. This has disappeared in the right (case 2) figure, showing re-attachment of the inner leg...

X-ray spectroscopy has also been applied to the interpretation of solar spectra, which are emitted by solar flares. Now stellar objects are under investigation by X-ray satellites such as Chandra and XMM. Whereas the present X-ray telescopes are medium resolution devices, the next generation (Constellation-X, XEUS) will provide sufficient spectral resolution for detailed analysis. The spectra from distant object usually suffer from low statistics solar flares have low emission time and the observation time of stellar objects is limited. In addition, the electron distribution is not Maxwellian, in general, and some of the spectral lines may be polarized. Therefore, verified theoretical data are of great importance to interpret solar and stellar spectra, where they provide the only source of information on the plasma state. 

As a future plan, we would like to explore a new field where atomic and nuclear physics are related in plasmas and systemize them. Extensions of our research to non-equilibrium, non-thermal and non-isotropic plasma, especially polarization spectroscopy are considered. We would like to develop quantum molecular dynamics for plasma-wall interactions, plasma radiation science, high-density plasma states, and atomic processes in high fields. These... 

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