Jet phenomena above zero points of coronal magnetic field

Some phenomena are observed in the solar corona in far violet and X-radiation. They are short-lived plasma jets of different scales from huge X-jets of more than 300 Mm spread to numerous small jets of sizes typical for macrospicules. The last ones are especially evident in polar coronal holes. They closely adjoin with tiny bright loops and concur with their sudden brightening and increase in size. The geometric form of jets and their location testify to the fact that they arise near zero critical points of coronal magnetic field. These points arise in coronal holes due to emergence of small bipolar or unipolar magnetic formations within large-scale unipolar sells. Polar jets show the evident vertical plasma motion in a coronal hole. This motion brings a significant impulse and mass into the solar wind flux. Research into polar jet dynamics allows us to make clear some details in the problem of fast solar wind acceleration.