Energy exchanges in reconnection outflows

Abstract

Abstract. Reconnection outflows are highly energetic directed flows that interact with the ambient plasma or with flows from other reconnection regions. Under these conditions the flow becomes highly unstable and chaotic, as any flow jets interacting with a medium. We report here massively parallel simulations of the two cases of interaction between outflow jets and between a single outflow with an ambient plasma. We find in both case the development of a chaotic magnetic field, subject to secondary reconnection events that further complicate the topology of the field lines. The focus of the present analysis is on the energy balance. We compute each energy channel (electromagnetic, bulk, thermal, for each species) and find where the most energy is exchanged and in what form. The main finding is that the largest energy exchange is not at the reconnection site proper but in the regions where the outflowing jets are destabilizied.

Dissipation in relativistic pair-plasma reconnection: revisited

“…The heat flow carries more energy than the matter flux in the outflow region, however, the enthalpy flux is a major carrier of the outgoing energy. This is consistent with the previous two-fluid simulation [28] and extends previous nonrelativistic results [24,25,26,27]. It is reasonable that the upstream magnetic energy is transferred to the plasma internal energy, a energy of a high-entropy state, through a dissipative process like magnetic reconnection.…”

Structure and Dynamics of Three‐Dimensional Magnetotail Reconnection

“…In addition to the event‐driven PIC simulation, we also carried out a 3‐D simulation starting with a Harris sheet initial distribution instead of the MHD‐based initial state (Lapenta et al, , ). The results from that simulation were used to help us interpret the much more complex results from the event simulation.…”

Nonlinear waves and instabilities leading to secondary reconnection in reconnection outflows

“…Recently, the energy budget has been analysed in detail (Lapenta et al. 2016 b ) and a large fraction of the energy is deposited as particle energization, while a significant fraction is also transported by the Poynting flux.…”

“…The region of secondary instabilities in the outflow shows strong parallel and perpendicular energization caused by the conversion of electromagnetic energy (i.e. J e • E) (Lapenta et al 2014a(Lapenta et al , 2016b.…”

“…All these instabilities can cause strong deformation of the flow, leading possibly to turbulence (Pucci et al 2017), energy exchange (Lapenta et al 2016b) and secondary reconnection (Lapenta et al 2015).…”