Magnetic reconnection is a process by which oppositely directed magnetic field lines passing through a plasma undergo dramatic rearrangement, converting magnetic potential into kinetic energy and heat 1,2. It is believed to play an important role in many plasma phenomena including solar flares 3,4 , star formation 5 and other astrophysical events 6 , laser-driven plasma jets 7-9 , and fusion plasma instabilities 10. Because of the large differences of scale between laboratory and astrophysical plasmas, it is often difficult to extrapolate the reconnection phenomena studied in one environment to those observed in the other. In some cases, however, scaling laws 11 do permit reliable connections to made, such as the experimental simulation of interactions between the solar wind and the Earth's magnetosphere 12. Here we report well-scaled laboratory experiments that reproduce loop-top-like X-ray source emission by reconnection outflows interacting with a solid target. Our experiments exploit the mega-gauss-scale magnetic field generated by interaction of a high-intensity laser with a plasma to reconstruct a magnetic reconnection topology similar to that which occurs in solar flares. We also identify the separatrix and diffusion regions associated with reconnection in which ions become decoupled from electrons on a scale of the ion inertial length. A major objective of laboratory astrophysics is to simulate the fundamental nature of astrophysical plasma physics processes in a laboratory environment so that certain astrophysical phenomenon can be studied in a controlled manner 13. High energy density facilities, such as high-powered lasers and Z-pinches, can provide such opportunities 14 , for example, direct measurements of opacity 15 , equations of state 16 , and photoionized plasmas 17,18 , as well as the similarity of physics, such as certain hydrodynamic phenomena of jets 19 and shocks 20 where a scaling law between astrophysical and laboratory plasma systems can be applied. As a fundamental cause of many plasma energy conversion processes, magnetic reconnection (MR) is certainly a high priority of such studies. Masuda et al. 21 observed the loop-top X-ray source in solar flares using the YOHKOH satellite and proposed that two antiparallel magnetic fields were merged above an arcade of closed loops as outflow jets from the reconnection point collided with high-density plasmas on the loop to produce a hot X-ray region. Ultraviolet 22 and X-ray 23,24 observations of plasma

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