  One of the main science questions of the Solar Orbiter and Parker Solar Probe
missions deals with understanding how electrons in the lower solar corona are
accelerated and how they subsequently access interplanetary space. We aim to
investigate the electron acceleration and energy release sites as well as the
manner in which accelerated electrons access the interplanetary space in the
case of the SOL2021-02-18T18:05 event, a GOES A8 class microflare associated
with a coronal jet. This study takes advantage of three different vantage
points, Solar Orbiter, STEREO-A, and Earth, with observations ranging from
radio to X-ray. Multi-wavelength timing analysis combined with UV/EUV imagery
and X-ray spectroscopy by Solar Orbiter/STIX (Spectrometer/Telescope for
Imaging X-rays) is used to investigate the origin of the observed emission
during different flare phases. The event under investigation satisfies the
classical picture of the onset time of the acceleration of electrons coinciding
with the jet and the radio type III bursts. This microflare features prominent
hard X-ray nonthermal emission down to at least 10 keV and a spectrum that is
much harder than usual for a microflare with a spectral index of 2.9. From
Earth's vantage point, the microflare is seen near the limb, revealing the
coronal energy release site above the flare loop in EUV, which, from STIX
spectroscopic analysis, turns out to be hot (at roughly the same temperature of
the flare). Moreover, this region is moving toward higher altitudes over time
(about 30 km/s). During the flare, the same region spatially coincides with the
origin of the coronal jet. We conclude that the energy release site observed
above-the-loop corresponds to the electron acceleration site, corroborating
that interchange reconnection is a viable candidate for particle acceleration
in the low corona on field lines open to interplanetary space.
