Charge states of heavy ions, as determined from the parameters of solar energetic particle spectra

The charge states of He, C, O, and Fe ions are determined for 51 gradual solar energetic particle (SEP) events of solar cycle 23 using the parameters of the particle energy spectra consisting of two power-law regions separated by the so-called knee. Experimental data from the GOES satellites (protons) and ULEIS (all particles) and SIS (H, C, O, Fe ions) instruments are employed. The charge states of the heavy ions are found to be independent of the SEP event magnitude and particle energy (in the interval of 0.3 to 30 MeV/nucleon).