Explore the fundamentals of plasma diagnostics in this introductory lecture from MIT's Principles of Plasma Diagnostics course. Discover the importance of plasma diagnostics and gain insights into the types of plasmas studied in the field. Learn from instructor Jack Hare as he lays the groundwork for understanding plasma measurement techniques and their applications. Delve into the reasons behind the need for plasma diagnostics and the characteristics of plasmas that make them subjects of scientific interest.