Charge-to-mass fractionation in solar energetic particles Original Research Article

The observed strong isotopic fractionation in solar energetic particle events relative to solar wind abundances is explained as a possible three-step process: 1) Depending on their charge-to-mass ratio, ions are selectively pre-accelerated by plasma waves in the solar atmosphere or in interplanetary space. 2) Efficiently pre-accelerated ion species are preferentially injected into 3) first-order Fermi acceleration at coronal or interplanetary shocks.