International audienceMultipoint or multichannel observations in plasmas can frequently be modelled as an instantaneous mixture ofcontributions (waves, emissions, ...) of different origins. Recovering the individual sources from their mixturethen becomes one of the key objectives. However, unless the underlying mixing processes are well known,these situations lead to heavily underdetermined problems. Blind source separation aims at disentangling suchmixtures with the least possible prior information on the sources and their mixing processes. Several powerfulapproaches have recently been developed, which can often provide new or deeper insight into the underlyingphysics.This tutorial paper briefly discusses some possible applications of blind source separation to the field ofplasma physics, in which this concept is still barely known. Two examples are given. The first shows howconcurrent processes in the dynamical response of the electron temperature in a tokamak can be separated. Thesecond example deals with solar spectral imaging in the Extreme UV and shows how empirical temperaturemaps can be built.