Physical parameters of solar X-ray jets

We derived the physical parameters of X-ray jets and associated hares using the high-resolution data taken with the soft X-ray telescope aboard Yohkoh . We analyzed 16 X-ray jets and found the following properties of the jets and the footpoint flares: (1) the temperatures and density of the jets, res pectively, are 3-8 MK (average: 5.6 MK) and 0.7-4.0 x 10(9) cm(-3) (average : 1.7 x 10(9) cm(-3)), (2) the temperatures of the jets are similar to thos e of the footpoint flares, (3) the thermal energies of the jets are 10(27)- 10(29) ergs, which is 1/4 to 1/7 of those of the footpoint flares, (4) the apparent velocity of the jets is usually slower than the sound speed, and ( 5) there is a correlation between the temperatures of the jets and the size s (square root of area) of the footpoint flares. On the basis of these resu lts, we find that the temperatures of a jet and a footpoint flare are deter mined by the balance between heating flux and conductive flux and that the mass of a jet is comparable to the theoretical value based on the balance b etween conductive flux and enthalpy flux carried by the evaporation flow. T hese results suggest that X-ray jets are evaporation hows produced by the r econnection heating.