On the Performance of Multi-Instrument Solar Flare Observations During Solar Cycle 24

Area of Science:

• Solar Physics
• Space Weather
• Astrophysics

Background:

• Coordinated observations across multiple space-based solar observatories enhance understanding of solar flare physics.
• Previous efforts focused on coordinating observations, but a quantitative analysis of multi-instrument flare coverage was lacking.

Purpose of the Study:

• To develop a technique for retrospectively searching archival data for solar flares observed by combinations of specific instruments.
• To quantify the extent of multi-instrument co-observations of solar flares.

Main Methods:

• A retrospective search of archival databases was performed for flares jointly observed by RHESSI, SDO/EVE, Hinode (EIS, SOT, XRT), and IRIS.
• Statistical analysis was used to compare observed co-observation rates with expected rates assuming independent instrument operation.

Main Results:

• Out of 6953 C1+ flares observed over 6.5 years, 40 were observed by 6 or more instruments simultaneously.
• The number of flares co-observed by 3 or more instruments was higher than expected under independent operation.
• Significantly more flares were observed by larger numbers of instruments than predicted by chance.

Conclusions:

• Space-based solar observatories frequently acted in cooperation, or at least had aligned goals, leading to higher-than-expected multi-instrument flare coverage.
• An interactive tool, Solar Flare Finder, is now available to facilitate searches for co-observed flare events.
• The findings inform future coordinated observation strategies for upcoming missions like DKIST, Solar Orbiter, and Parker Solar Probe.