Resonant excitation of Fe14+ observed with a compact electron beam ion trap

Abstract We present extreme ultraviolet spectra of highly charged Fe ions observed with a compact electron beam ion trap as a function of monoenergetic electron beam energy. For 3 s 3 p – 3 s 3 d lines in Fe XV, strong intensity enhancement at a specific electron energy is confirmed. The enhancement is assigned as the resonant excitation via dielectronic capture followed by autoionization. The resonance contribution to line intensity ratio, which is important for the diagnostics of astrophysical plasmas, is discussed.