Plasma is known to be the fourth state of matter. It is entirely different when compared with three well known basic states of matter. Solid, liquids and gas are three states of any substance which we feel around us. But out there away from earth into the space, matter exist in form of plasma state. By nature the plasma do not exist itself on earth. However, it can be created at certain condition and advanced equipments. From the concept of temperature and pressure relation to the state of matter. We have an idea on the condition that occurs when a change is made in temperature and pressure of matter. For example, its physical transfer from one state to another state. Solid ice turns to water and water to steam when temperature is increased by supplying heat to it at a fixed pressure. Similarly phase change occurs in vice versa conditions.
When the gas of any element is heated further. Eventually rising it temperature so that the particles are ionised forming a ionised gas. Ionization by temperature increase, leads to the gas state that have equal number of negative and positive charged particles. The gas at this state is called plasma. The temperature of plasma would be around 100,000oC and an example of ionised gas is, H2 —> H+ + H+ + 2e– here hydrogen molecule splits into individual hydrogen atom with positive charge and it opposite charge particles electrons in equal number.
Plasma’s made by man are mercury and sodium vapour lamps, glow tubes, arc welders etc,. Producing plasma deals with high energy consumption during one of the steps in the process. Of-course it is electrically neutral state with no net electrical charge to attain this it requires vast amount of energy which will activate the electron to jump away from it nucleus region.
Methods that help to produce the plasma the fourth state of matter and supply enough heat
|Beam injection||Ac and rf discharges|
|Electron beam||Hot emitting electrodes|
|Photo ionisation||Pulsed discharged, capacitor discharge, inductive discharge which is known as shock waves|
|Contact heating||Hot or emitting electrodes|
|Plasma beam||Cold electrodes|
|Energetic neutral beam||Ion or electron cyclotron resonance|
By applying vacuum and collisional interaction plasma is generated at laboratories. Plasma becomes a fuel which can produce energy for long duration without interruption, in a controlled thermonuclear fusion. It can make space travel easier by replacing the present rocket engines with rocket propulsion systems built with plasma rocket engines.
Present stage nuclear fusion reactors use fuels in plasma state.