Heating and jet formation by hydrodynamic cumulation in the solar atmosphere

The solar transition region is the site of supersonic plasma jets and spora dic radiative events, whose origin and physical nature have not been unders tood. Here we show that ubiquitous small-scale magnetic flux "tubes," const antly emerging from subsurface layers, may cause the formation of plasma je ts and a sporadic excess of temperature near the solar surface. These flux tubes collide and reconnect, creating a sling-shot effect that generates co mplex three-dimensional shock waves with the curved surface. Self-focusing of these shocks occurs as they propagate upward in the rarefied atmosphere. Depending on the geometry of the shock collision, highly concentrated ener gy may be converted entirely into either heat or strong jets, or distribute d between the two.