Speaker
Description
The GOES/XRS data show low-level soft X-ray emissions prior to a
flare in a "hot onset" precursor of the main flare development
(2021MNRAS.501.1273H). This phenomenon provides clear evidence for
a heating process not identifiable with the impulsive-phase energy
release. The hot onset phase may last for tens of seconds to minutes,
characterized by steady growth of emission measure at characteristic
isothermal temperatures of 10-15 MK and no clear pattern of temperature
increase. The newer GOES-R data also show this effect, providing
higher time resolution (1 s) and better noise properties, although
with higher background levels. I characterize these new data and
discuss interpretations in terms of physical processes in the context
of the AIA imagery.
