Revised View of Solar X-Ray Jets

Abstract:

We investigate the onset of ~20 random X-ray jets observed by Hinode/XRT. Each jet
was near the limb in a polar coronal hole, and showed a ''bright point'' in an
edge of the base of the jet, as is typical for previously-observed X-ray jets. We
examined SDO/AIA EUV images of each of the jets over multiple AIA channels,
including 304 Ang, which detects chromospheric emissions, and 171, 193, and 211 Ang,
which detect cooler-coronal emissions. We find the jets to result from eruptions
of miniature (size <~10 arcsec) filaments from the bases of the jets. In many
cases, much of the erupting-filament material forms a chromospheric-temperature
jet. In the cool-coronal channels, often the filament appears in absorption and
the hotter EUV component of the jet appears in emission. The jet bright point forms
at the location from which the miniature filament erupts, analogous to the
formation of a standard solar flare arcade via flare (``internal'') reconnection
in the wake of the eruption of a typical larger-scale chromospheric filament. The
spire of the jet forms on open field lines that presumably have undergone
interchange (''external'') reconnection with the erupting field that envelops and
carries the miniature filament. This is consistent with what we found for the
onset of an on-disk coronal jet we examined in Adams et al. (2014), and the
observations of other workers. It is however not consistent with the basic
version of the ''emerging-flux model'' for X-ray jets. This work was supported by
funding from NASA/LWS, Hinode, and ISSI.