Electrical discharges applied in a plasma source

Plasma source

Plasma sources generate plasmas.Excitation of a plasma requires partial ionization of neutral atoms and/or molecules of a medium.There are several ways to cause ionization:collisions of energetic particles, strong electric fields acting on bond...

 for the generation of plasma

Plasma (physics)

In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...

s can be classified by the frequency of the exciting field. A rough classification is:

• Direct current discharge (DC)
• Pulsed DC discharge (kHz)
• Radio-frequency discharge (MHz) - sustained by two electron heating mechanisms: ohmic heating
  Joule heating
  Joule heating, also known as ohmic heating and resistive heating, is the process by which the passage of an electric current through a conductor releases heat. It was first studied by James Prescott Joule in 1841. Joule immersed a length of wire in a fixed mass of water and measured the temperature...
  
   and stochastic heating
• Microwave discharge (GHz)
• Laser plasma (PHz)

The quality of the coupling

Coupling (physics)

In physics, two systems are coupled if they are interacting with each other. Of special interest is the coupling of two vibratory systems by means of springs or magnetic fields, etc...

 of an exciting field of given frequency

Frequency

Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...

 to a
charged particle

Charged particle

In physics, a charged particle is a particle with an electric charge. It may be either a subatomic particle or an ion. A collection of charged particles, or even a gas containing a proportion of charged particles, is called a plasma, which is called the fourth state of matter because its...

 depends on the position and shape of the plasma resonance

Resonance

In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...

.
It critically determines the character of the electrical discharge. If the
more massive ion

Ion

An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...

s cannot follow the oscillating electromagnetic field

Electromagnetic field

An electromagnetic field is a physical field produced by moving electrically charged objects. It affects the behavior of charged objects in the vicinity of the field. The electromagnetic field extends indefinitely throughout space and describes the electromagnetic interaction...

, the exciting frequency is called high (HF). In this case, the main fraction of the power

Power (physics)

In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...

 is transferred to the electrons.

See also

• Plasma source
  Plasma source
  Plasma sources generate plasmas.Excitation of a plasma requires partial ionization of neutral atoms and/or molecules of a medium.There are several ways to cause ionization:collisions of energetic particles, strong electric fields acting on bond...
  
  
• Gas discharge