Relative contribution of electrons to the stormtime total ring current energy content

Abstract

We evaluate the relative importance of stormtime ring current electrons to protons by calculating the energy content ratio of electrons to protons for typical ring current energies inferred from observations and simulations. We analyze Explorer 45 measurements taken around the minimum Dst(=−171 nT) of the 17 December 1971 storm. We simulate the electron and proton ring current energy content during a hypothetical storm using drift‐loss simulations. From the data analysis, we find that electrons with energies of ∼1–50 keV and protons with energies of ∼10–200 keV contribute the most to the corresponding particle energy content. From both observations and simulations, the ring current electrons contribute only ∼1% as much energy content as ring current protons during quiet times. However, this ratio increases to ∼8–19% during storm main phase. Thus, the ring current electrons can contribute significantly to the ring current energy content during storms.