Magnetic reconnection is a leading mechanism for magnetic energy conversion and high-energy non-thermal particle production in a variety of high-energy astrophysical objects , including ones with relativistic ion-electron plasmas ( e.g. , microquasars or AGNs ) – a regime where first principle studies are scarce .
We present 2D particle-in-cell ( PIC ) simulations of low \beta ion-electron plasmas under relativistic conditions , i.e. , with inflow magnetic energy exceeding the plasma rest-mass energy . We identify outstanding properties : ( i ) For relativistic inflow magnetizations ( here 10 \leq \sigma _ { \mathrm { e } } \leq 360 ) , the reconnection outflows are dominated by thermal agitation instead of bulk kinetic energy .
( ii ) At large inflow electron magnetization ( \sigma _ { \mathrm { e } } \geq 80 ) , the reconnection electric field is sustained more by bulk inertia than by thermal inertia .
It challenges the thermal-inertia-paradigm and its implications .
( iii ) The inflows feature sharp transitions at the entrance of the diffusion zones .
These are not shocks but results from particle ballistic motions , all bouncing at the same location , provided that the thermal velocity in the inflow is far smaller than the inflow E \times B bulk velocity .
( iv ) Island centers are magnetically isolated from the rest of the flow , and can present a density depletion at their center .
( v ) The reconnection rates are slightly larger than in non-relativistic studies .
They are best normalized by the inflow relativistic Alfvén speed projected in the outflow direction , which then leads to rates in a close range ( 0.14–0.25 ) thus allowing for an easy estimation of the reconnection electric field .