1. The problem statement, all variables and given/known data 'Briefly describe two different kinds of plasmas and in each case describe how the plasma arises.' 2. Relevant equations http://en.wikipedia.org/wiki/Plasma_(physics) 3. The attempt at a solution I think i understand what a plasma is, but are there different types of plasma that fall into different categories? From the question it suggests different types are formed in different ways. What are these categories and how are the plasmas formed?