In situ evidence of magnetic reconnection in turbulent plasma

Magnetic reconnection is a universal process leading to energy conversion in plasmas(1). It occurs in the Solar System(2-7), in laboratory plasmas(8) and is important in astrophysics(9,10). Reconnection has been observed so far only at large-scale boundaries between different plasma environments(4-8). It is not known whether reconnection occurs and is important in turbulent plasmas where many small-scale boundaries can form. Solar(11) and laboratory(12) measurements as well as numerical simulations(13-16) indicate such possibility. Here we report, for the first time, in situ evidence of reconnection in a turbulent plasma. The turbulent environment is the solar wind downstream of the Earth's bow shock. We show that reconnection is fast and electromagnetic energy is converted into heating and acceleration of particles. This has significant implications for laboratory and astrophysical plasmas where both turbulence and reconnection should be common.