AUTHOR=Brooks David H. , Reep Jeffrey W. , Ugarte-Urra Ignacio , Warren Harry P. 

TITLE=On orbit performance of the solar flare trigger for the Hinode EUV imaging spectrometer

JOURNAL=Frontiers in Astronomy and Space Sciences

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2023.1149831

DOI=10.3389/fspas.2023.1149831

ISSN=2296-987X

ABSTRACT=<p>We assess the on-orbit performance of the flare event trigger for the Hinode EUV Imaging Spectrometer. Our goal is to understand the time-delay between the occurrence of a flare, as defined by a prompt rise in soft X-ray emission, and the initiation of the response observing study. Wide (266<sup><italic>″</italic></sup>) slit patrol images in the He II 256.32 Å spectral line are used for flare hunting, and a reponse is triggered when a pre-defined intensity threshold is reached. We use a sample of 13 <inline-formula id="inf1"><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>&gt;</mml:mo></mml:math></inline-formula> M-class flares that succesfully triggered a response, and compare the timings with soft X-ray data from GOES, and hard X-ray data from RHESSI and Fermi. Excluding complex events that are difficult to interpret, the mean on orbit response time for our sample is 2 min 10 s, with an uncertainty of 84 s. These results may be useful for planning autonomous operations for future missions, and give some guidance as to how improvements could be made to capture the important impulsive phase of flares.</p>