How are cosmic rays from solar flares different from galactic cosmic rays?

Cosmic rays originating from solar flares differ from galactic cosmic rays (GCRs) primarily in their origin, energy levels, and spectral characteristics.

While GCRs originate from sources within the Milky Way Galaxy, solar cosmic rays are accelerated by strong magnetic fields near the Sun during solar flares and coronal mass ejections.12

Key differences include:

• Energy Spectrum: The energy spectrum of solar particles decreases more rapidly as energy increases compared to GCRs. Additionally, solar particle energy rarely exceeds approximately 1 GeV per nucleon, whereas GCRs can reach significantly higher energies.1
• Variability: The energy spectrum of solar cosmic rays exhibits great variability between different flare events, unlike the more consistent nature of GCRs.1
• Composition: Both consist largely of protons with smaller amounts of helium and heavier nuclei, but solar particle observations are uniquely used to study the Sun’s helium abundance, which is otherwise difficult to measure.1