Distribution of the analyzed SEPs with different >100 MeV proton fluxes (J₁₀₀) at the microwave flux density plane “S₉ vs. S₁₅”.  The following points deserve attention:

(1) General correspondence takes place between intensities of microwave bursts and proton fluxes – J₁₀₀ increases when S₉ and S₁₅ rise.

(2) Among events with relatively weak radio fluxes (S₉, S₁₅ <1000 sfu), weak proton fluxes (J₁₀₀<1 pfu) under soft radio spectra (S₉>S₁₅) dominate.

(3) Powerful microwave bursts (S₉, S₁₅>3000–10000 sfu) with hard radio spectra (S₉<S₁₅) correspond to majority of powerful proton fluxes (J₁₀₀ >10 pfu).

(4) SEPs with moderate proton fluxes rank intermediate positions.