What are plasmas?

Answer 1

Plasmas are quasineutral gases of charged and neutral particles that exhibit collective behaviour.

The collective behaviour can be explained by taking an example of air molecule. As the air molecule is neutral there is no any electromagnetic force between them. Also the gravitational force between them is negligble as is their mass. So an air molecule travels randomly until it makes a collision with another molecule and its motion is governed by a series of several such collisions. But in case of plasma there are charged particles. So there is electromagnetic force between them. As the charged particles move around, an electric field is created between them. Also the motion of charged particles causes current flow thus giving rise to magnetic field. So the motion of a particle of a plasma is governed by the particle even at far places. Thus collective behaviour refers to the condition that the motion of a particle depends not only the local conditions but also on the remote regions.

Quasineutral means that the number density (number per unit volume) of ions is equal to that of electrons. However, a plasma should not be so neutral that all the interesting electromagnetic forces between the particles vanish...........

Answer 2

Plasma can refer to the clear component in blood after the red and white cells have been removed.

Plasma as in "plasma screen TV" refers to a soup of electrons and protons in a highly charged electrical field with unusual proprties. In this plasma the molecules are very disrupted and confused an have unusual properties.

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Also, in physics, plasma is the fourth state of matter where particles are heated to the point where the electrons are "stripped" away from the nuclei.