SIMULTANEOUS SYNCHROTRON AND ADIABATIC EFFECTS IN MULTIPLY SHOCKED JETS IN EXTENDED EXTRAGALACTIC RADIO-SOURCES

As part of the effort to understand the radio spectra of extragalactic radio sources, we have incorporated the effects of simultaneous synch rotron and adiabatic processes for jet plasma crossing several shocks, which could produce multiple radio hot spots within the lobes. Obliqu e shocks compress the transverse component of the magnetic field and a lso boost the energy of the plasma within the shock regions. We make t he assumption that more powerful jets typically pass through more shoc ks before terminating subsonically. A model incorporating these effect s is able to reproduce the spectral evolution usually observed in the hot spots and lobes of high-luminosity double radio sources. Our resul ts also support Gopal-Krishna & Wiita's view that the observed correla tion between steeper indices and higher radio power results when a jet passes through a sequence of oblique shocks within the lobe of a radi o source.