Side on Interferometry at 10.6_mym of Theta_Pinch Plasmas

An experiment for measuring electron density spatially resolved with high time resolution is described. The experiment was performed side on on a Theta pinch plasma. The light source (TEA-CO2 laser), the window problem, the area detector for the interferogram are discussed. The sensitivity of the technique is 1–2×1015 electrons/cm2. Some examples of measured density profiles show that the method may be used effectively on toroidal plasma machines.