The natural source of both plasma and electromagnetic radiation (EMR) is the sun. There are various similarities such as the presence of electric and magnetic field in both EMR and plasma. Both transport contain energy and are ubiquitous in the universe. However, there are large differences between EMR and plasma.
Differences between EMR and plasma
EMR is energy that propagates through a medium in the form of EM waves. It has an electric and magnetic field which oscillate in phase perpendicular to each other and to the direction of propagation. EMR exists in different wavelengths and frequencies ranging from gamma rays to radio waves which make up the EM spectrum. Plasma is categorized as the fourth state of matter because its character is more complex than solid, liquid or gas state. It is electrically charged particles at high energy level. It is made up of ionized gas which contains almost equal amounts of negatively charged electrons and positively charged ions. The ability of the positive and negative charges to move independently makes the plasma electrically conductive. Due to its electrical conductivity, plasma has electric and magnetic fields. Therefore, plasma produces EMR among other types of waves. Types of plasma waves depend on its temperature and the presence of magnetic field. Plasma waves do not propagate very far in plasma and are strongly influenced by the magnetized plasma when they do propagate. On the other hand, EM waves can propagate away from their source with little interaction with the surrounding medium.
Because EMR and plasma are interrelated, it is important for us to understand the difference between them. Plasma is a state of matter while EMR is a form of energy.