图片名称

Plasma properties

Keywords:

Published on:

25 Aug,2020

Plasma properties:

Plasma state is often called "supergas", it and gas have many similarities, such as: no definite shape and volume, has liquidity, but also has a lot of unique properties. The particles in a plasma have a population effect, and as long as a particle disturbance, the disturbance propagates to the ionized particles in each plasma. Plasmas themselves are good conductors.

 

A plasma differs from a normal gas in that it is an ionized gas. Due to the presence of negatively charged free electrons and positively charged ions, there is a high conductivity and strong coupling of electromagnetic fields: charged particles can be coupled to the electric field, and charged particle flows can be coupled to the magnetic field. Plasma was described using electrodynamics, and a theory called magnetohydrodynamic was thus developed.

 

Plasma:

Unlike ordinary gases, a plasma contains two or three different components: free electrons, positively charged ions and unionized atoms. This allows us to define different temperatures for different components: electron temperature and ion temperature. In mildly ionized plasma, the ion temperature is generally much lower than the electron temperature, which is called "low temperature plasma". Highly ionized plasmas with high ionic and electron temperatures are called "high temperature plasmas". The interaction between the constituent particles of the plasma is also much larger than that of ordinary gases.

 

Rate distribution:

The velocity distribution of general gas satisfies The Maxwell distribution, but the plasma may deviate from the Maxwell distribution due to its coupling with the electric field.

 

Surface isoexciter effect:

Experiment we put metal particles as plasma (metal crystal because of its internal exist a large number of free electrons can move - - with quantitative charge, free distribution, collision and will not lead to the disappearance of the charge - so the metal crystals can be seen as the electron plasma), due to the dielectric coefficient of metal in the visible and infrared wavelengths is negative, so when the metal and dielectric composite as composite structure can happen a lot of interesting phenomenon.

 

When light waves (electromagnetic waves) incident to the metal and medium interface, free electrons on the surface of the metal collective oscillation occurs, if the oscillation frequency of the consistent with the frequency of the incident light wave will produce resonance, then to form a special electromagnetic mode: electromagnetic field were limited within the scope of the metal surface is small and enhancement, this phenomenon is called from the excimer phenomenon such as surface. This electromagnetic field enhancement effect can effectively improve the molecular fluorescence signal, atomic high harmonic generation efficiency, and molecular Raman scattering signal. On a macroscopic scale, this phenomenon is manifested as a significant increase in the transmittance of metallic crystals at a specific wavelength.

Plasma properties

Hot Products

Related articles