Emission of plasma from a graphite lead placed in a microwave oven

Plasmas generated by microwaves have aroused curiosity over the past few years. In addition to being impressive, they have a practical use in industry or research. In this paper, we study a plasma initiated by placing a pencil rod into a microwave oven. We find the optimal conditions to create a plasma and we analyse its composition by spectroscopy in the visible range. We show that the plasma is mainly composed of elements coming from the pencil rod.