On the parametric excitation of thermoelectric instability in a liquid layer open to air

Results are given about the parametric excitation of thermoelectric instabi lity in a liquid semiconductor or an ionic melt layer subject to a harmonic ally time varying heat flux normal to its top open surface. First, it is sh own that for a purely thermoelectric instability the 'integer' disturbances are the most dangerous ones for the liquid quasiequilibrium. Then the boun daries of instability and characteristics of critical disturbances are foun d for the cases of coupled phenomena between thermoelectric effects and sur face tension gradients and thermoelectric effects and buoyancy. Both 'half- integer' and 'integer' modes were studied. Qualitative and quantitative res ults are provided for the experimental observation of our predictions. (C) 1999 Elsevier Science Ltd. All rights reserved.