The thermal evolution of the jets in SS 433

Recent X-ray measurements of SS433 with the EXOSAT satellite indicate that the bases of the jets consist of thermally radiating matter at X-ray temperatures. The authors show in a detailed numerical treatment how the expected thermal instability in the cooling flow evolves, leading to a clumpy medium as deduced from optical observations. X-ray spectral and luminosity constraints allow a much better understanding of the evolution and energetics of the jets and it is argued that the required reheating of the cold blobs may be achieved by dissipation of a minute fraction of the jet's kinetic energy.