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The plasma approximation: The plasma approximation applies when the plasma parameter Λ, [26] representing the number of charge carriers within the Debye sphere is much higher than unity. [ 19 ] [ 20 ] It can be readily shown that this criterion is equivalent to smallness of the ratio of the plasma electrostatic and thermal energy densities.
The plasma collisionality is defined as [4] [5] =, where denotes the electron-ion collision frequency, is the major radius of the plasma, is the inverse aspect-ratio, and is the safety factor. The plasma parameters m i {\displaystyle m_{\mathrm {i} }} and T i {\displaystyle T_{\mathrm {i} }} denote, respectively, the mass and temperature of the ...
This glossary of chemistry terms is a list of terms and definitions relevant to chemistry, including chemical laws, diagrams and formulae, laboratory tools, glassware, and equipment. Chemistry is a physical science concerned with the composition, structure, and properties of matter , as well as the changes it undergoes during chemical reactions ...
The various modes can also be classified according to whether they propagate in an unmagnetized plasma or parallel, perpendicular, or oblique to the stationary magnetic field. Finally, for perpendicular electromagnetic electron waves, the perturbed electric field can be parallel or perpendicular to the stationary magnetic field.
Matter in the plasma state has variable volume and shape, and contains neutral atoms as well as a significant number of ions and electrons, both of which can move around freely. The term phase is sometimes used as a synonym for state of matter, but it is possible for a single compound to form different phases that are in the same state of matter.
A nonthermal plasma, cold plasma or non-equilibrium plasma is a plasma which is not in thermodynamic equilibrium, because the electron temperature is much hotter than the temperature of heavy species (ions and neutrals).
To induce plasma, a spark is produced at the electrodes at the gas outlet. Argon is one example of a commonly used rarefied gas. The high temperature of the plasma allows the atomization of molecules and thus determination of many elements, and in addition, for about 60 elements the degree of ionization in the torch exceeds 90%.
Plasma etching is a form of plasma processing used to fabricate integrated circuits. It involves a high-speed stream of glow discharge of an appropriate gas mixture being shot (in pulses) at a sample. The plasma source, known as etch species, can be either charged or neutral (atoms and radicals).