  We consider electron impact-driven single and double ionization of magnesium
in the 10-100 eV energy range. Our classical Hamiltonian model of these (e, 2e)
and (e, 3e) processes sheds light on their total cross sections and reveals the
underlying ionization mechanisms. Two pathways are at play in single
ionization: Delayed and direct. In contrast, only the direct process is
observed in double ionization, ruling out the excitation-autoionization
channel. We also provide evidence that the so-called TS2 (Two-Step 2) mechanism
predominates over the TS1 (Two-Step 1) mechanism, in agreement with
experiments.
