A method for measuring electron temperature and density in plasma by the scattering of laser radiation on electrons. Electromagnetic radiation interacts with a charged particle, which then sends out a photon of the same wavelength, usually perpendicular to its direction of motion, resulting in a reflection of the incident wave. The wavelength of the reflected signal shifts due to the Doppler effect depending on the speed and direction of the particles. From this, the temperature of the plasma can be derived. The electron density can then be determined from the intensity of the scattered signal. Thomson laser scattering provides accurate local measurements of these two important plasma parameters, and with the high repetition rate of the laser, it also allows the detection of fast events in the plasma, such as density and temperature changes after pellet injection.