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Plasma automatic cleaning machine ion and ionization degree

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28 Oct,2020

Plasma automatic cleaning machine ion and ionization degree:

 

In general, the basic particles of plasma consist of electrons, ions and neutral particles. Let the electron density be Ne, the ionic density be Nj, and the density of neutral particles be Ng. Obviously, for a plasma with a single atmosphere and only first-order ionization, Ne=Ni exists, and n can be used to represent the density of any charged ion in the two, abbreviated as plasma density. Of course, mixed gas plasma or plasma with multiorder ionization may contain different valence ions or different kinds of neutral particles, so the electron density and ion density in the equiionization body are not the same.

 

When α<0.01, it is called weak ionization plasma. When 1> α> is 0.01, it is called strongly ionized plasma. When α=1, it is called a fully ionized plasma. In thermodynamic equilibrium systems, where there is an equilibrium between ionization and ion recombination, ionization degree α depends only on the type, density, and temperature of the particles. The following table shows the variation of ionization degree α of nitrogen plasma with temperature under the condition of thermal equilibrium at atmospheric pressure. As can be seen from the table, with the increase of temperature, the ionization degree increases rapidly, but if you want to get the plasma automatic cleaning machine plasma ionization, it must reach tens of thousands of degrees of high temperature. Variation of nitrogen plasma ionization α with temperature at atmospheric thermal equilibrium.

T/K

α

300

10^-122

5000

3.2×10^-7

10000

0.0065

15000

0.22

20000

0.82

 

There is a equilibrium between ionization and recombination in plasma. If the equilibrium is reached at temperature T, the relationship between ionization degree α and ionization conditions can be described by the Equation of Saha (Mcghnad Saha, 1893~1956, Indian astrophysicist).

 

P stands for pressure (Torr, 1 Torr=1.333 22×10^2Pa); T is for temperature (K); W stands for ionization potential (eV) of gas molecules (atoms); K represents Boltzmann constant (1.380 6505×10^ -23j/k); Alpha stands for ionization. Lowering the gas pressure, using a gas with a low ionization potential, or using a high electron temperature all contribute to increased ionization.

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