BIDIRECTIONAL PLASMA JETS PRODUCED BY MAGNETIC RECONNECTION ON THE SUN

Magnetic reconnection, the process by which magnetic lines of force br eak and rejoin into a lower-energy configuration, is considered to be the fundamental process by which magnetic energy is converted into pla sma kinetic energy(1). The Sun has a large reservoir of magnetic energ y, and the energy released by magnetic reconnection has been invoked t o explain both large-scale events, such as solar flares(2,3) and coron al mass ejections(4), and small-scale phenomena, such as the coronal a nd chromospheric microflares that probably heat and accelerate the sol ar wind(5,6). But the observational evidence for reconnection is large ly indirect, resting on observations of variations in solar X-ray morp hology and sudden changes in the magnetic topology(7,8), and on the ap parent association between some small-scale dynamic events and magneti c bipoles(9,10). Here we report ultraviolet observations of explosive events in the solar chromosophere that reveal the presence of bi-direc tional plasma jets ejected from small sites above the solar surface. T he structure of these jets evolves in the manner predicted by theoreti cal models of magnetic reconnection(11,12), thereby lending strong sup port to the view that reconnection is the fundamental process for acce lerating plasma on the Sun.