Distinguishing between ESPE–superflare causation hypotheses

Ascertain whether extreme solar particle events are produced by superflares only rarely under favorable magnetic and heliospheric conditions (hypothesis ii) or whether extreme solar particle events and flares are not directly related and thus have incomparable statistics (hypothesis iii), given that a one-to-one correspondence between ESPEs and superflares has been rejected.

Background

The paper frames three hypotheses about the relationship between ESPEs and superflares: (i) a near one-to-one correspondence; (ii) ESPEs are produced by superflares but only rarely; (iii) ESPEs and flares are not directly related. Observational evidence rules out (i), but current data do not decide between (ii) and (iii).

Resolving this uncertainty is necessary to compare solar and stellar extreme-event statistics and to determine the physical conditions that allow efficient particle acceleration and escape during the most energetic eruptions.