Kirk, John

Poynting flux dissipation in jets.

Author list: John G. Kirk, Takanobu Amano, Iwona Mochol

Relativistic shocks are promising sites for the production of a nonthermal particle population, and, therefore, the nonthermal emission observed from jets. However, if they obey the standard MHD Rankine-Hugoniot jump conditions, they are not effective at dissipating the energy of a relativistic, magnetically dominated jet into particles.  A way out of this problem is possible if the incoming magnetic field fluctuates on a sufficiently short timescale. In this case, dissipation can proceed either by driven reconnection in the compressed downstream plasma, or by conversion of the fluctuation modes into a damped superluminal electromagnetic mode in a shock precursor.

I will report recent work on the latter scenario, concerning the stability of these modes, and present two-fluid simulations that explicitly demonstrate mode conversion in a shock precursor. The implications of these results for particle acceleration will be discussed.