# 3He-Rich Solar Energetic Particles from Sunspot Jets

## TL;DR

This study investigates rare high-energy 3He-rich solar energetic particle events, linking them to jets from large sunspots with complex magnetic fields, revealing new insights into their solar origins and acceleration mechanisms.

## Contribution

It identifies the solar sources of high-energy 3He-rich SEPs as jets from large, complex sunspots, expanding understanding beyond typical small active region sources.

## Key findings

- High-energy 3He-rich SEPs are associated with jets from large sunspots.
- These events lack type-II radio emissions but show type-III bursts.
- Photospheric magnetic complexity influences 3He acceleration to high energies.

## Abstract

Solar sources of suprathermal (<1 MeV/nucleon) 3He-rich solar energetic particles (SEPs) have been commonly associated with jets originating in small, compact active regions at the periphery of near-equatorial coronal holes. Sources of relatively rare, high-energy (>10 MeV/nucleon) 3He-rich SEPs remain unexplored. Here we present two of the most intense 3He-rich (3He/4He>1) SEP events of the current solar cycle 24 measured on the Advanced Composition Explorer at energy >10 MeV/nucleon. Although 3He shows high intensities, Z>2 ions are below the detection threshold. The events are accompanied by type-III radio bursts, but no type-II emission as typically seen for suprathermal 3He-rich SEPs. The corresponding solar sources were analyzed using high-resolution, extreme-ultraviolet imaging and photospheric magnetic field observations on the Solar Dynamics Observatory. We find the sources of these events associated with jets originating at the boundary of large sunspots with complex beta-gamma-delta magnetic configuration. Thus, details of the underlying photospheric field apparently are important to produce 3He to high energies in the examined events.