...I want to "slightly" change a field after finishing my two Masters... Facts: I'm in last year of Master of Mathematical Modelling in Prague (Czech Republic), focused on fluid mechanics. In the same time I'm in Paris at the university Paris Diderot finishing second year master "Mathematiques fondamentales" - pure math, but I specialize to PDEs. My supervisor in Prague is also mathematician who gave me more-less theoretical topic for my Diploma thesis. My intentions: I'm not so keen for pure stuff as my supervisors are (there is another one in Paris) and I would like to turn to more applied science. And I have strong desire to do something related to renewable energy sources. So If I consider my specialization so far, what come in my mind is some kind of water-renewables, like tidal or marine energy. I would like to stay in France for PhD or in UK. The problem: My supervisor expects me to come back to Czech Republic after this year and to continue pure stuff PhD there. How I should proceed ? I have a fear that if I'll tell him too early he will stop caring about my progress, which is important for me to have good looking CV, however in the same time I should be contacting scientists in new field ASAP for getting better chances to be accepted and for this I need good reference from my sup. I guess. (What would happen if I contact somebody and than he will write mail my sup. asking about me, while my sup. has no glue about my intentions...) I need advices... Please... Thanks.