Plasma is the fourth state of matter that can be reached in high energies. Normally, when atoms in a solid gain enough energy it goes to liquid phase, and then the phase transition is continued to the gas phase at higher energy levels, and then plasma is formed at extremely high temperatures. In a typical plasma, some or all of the electrons in an atom gain enough energy to overcome nucleus potential barrier and an ionized gas is formed. So, plasma contains free electron-ions and is able to conduct electricity. Since atoms are normally neutral, the plasma is electrically neutral. Plasma may contain magnetic fields as moving electric charges create them.
Plasma is not condensed enough that its constituent particles collide with each other frequently, so energy transfer and thermal equilibrium in plasma is not the same as the gas phase. Applying electromagnetic fields to the plasma, it may go unstable and a bunch of very fast particles appear in it, hence the plasma can possess different temperatures in different parts at a time; as the temperature of sun’s corona – made of plasma – can reach to millions of degree, while the temperature of the surface of the sun is about thousands of degrees (Figure 1).
Electromagnetic interactions are so important in the plasma as a result of electron-ion separation. Moreover, these interactions can occur at larger distances compared to the gas phase. So, waves in plasma, or organized motion of it, is very significant. Another noticeable feature of it is that it can be confined by using a magnetic field (Figure 2), a capability used in fusion energy research.
Plasma in the Universe
Plasma is the most abundant form of matter in the universe, as 99% of the seen universe is in the form of plasma. Stars, nebulas, and the aurora seen in the north and south pole are all made of plasma. We can also see it in everyday life in the form of a lightening, conductive gas in a fluorescent light bulb or a neon light bulb. In addition, it is a favorite field for the scientists to research.
What is Plasma Physics Used for?
Plasma has various applications in different fields, some of them are mentioned here:
- Medical sciences
- Healing wounds
- Cancer therapy
- Improve bone healing
- Eliminating biological hazards
- Cleaning the environment and surfaces (Plasma Cleaning)
- Functionalizing different surfaces
- Making hydrophilic or hydrophobic surfaces (You can read more about them here: Hydrophilicity and Hydrophobicity)
- Manufacturing computer chips
- Plasma TV
- Plasma lamp or globe
- Nuclear energy reactors
- Electron guns
- Rocket propulsion
- Plasma knife
VacCoat Coating Systems
Vacuum coating systems made by VacCoat Ltd. are optionally capable of performing the plasma surface cleaning process prior to the deposition. Some models which are equipped to the plasma cleaner option is magnetron sputter coater model DST1-300, desk sputter carbon coater equipped to turbo pump model DSCT, desk sputter carbon coater model DSCR, and triple target sputter coater model DST3.
Other Coating Systems