  A jet is a considerable amount of plasma being ejected from the chromosphere
or lower corona into the higher corona and is a common phenomenon. Usually, a
jet is triggered by a brightening or a flare, which provides the first driving
force to push plasma upward. In this process, magnetic reconnection is thought
to be the mechanism to convert magnetic energy into thermal, nonthermal, and
kinetic energies. However, most jets could reach an unusual high altitude and
end much later than the end of its associated flare. This fact implies that
there is another way to continuously transfer magnetic energy into kinetic
energy even after the reconnection. The picture described above is well known
in the community, but how and how much magnetic energy is released through a
way other than reconnection is still unclear. By studying a prominence-like jet
observed by SDO/AIA and STEREO-A/EUVI, we find that the continuous relaxation
of the post-reconnection magnetic field structure is an important process for a
jet to climb up higher than it could through only reconnection. The kinetic
energy of the jet gained through the relaxation is 1.6 times that gained from
the reconnection. The resultant energy flux is hundreds of times larger than
the flux required for the local coronal heating, suggesting that such jets are
a possible source to keep the corona hot. Furthermore, rotational motions
appear all the time during the jet. Our analysis suggests that torsional
Alfv\'en waves induced during reconnection could not be the only mechanism to
release magnetic energy and drive jets.

Solar and Stellar Astrophysics