Measurement of the Anomalous Zeeman Effect in Argon Plasma

In university physics courses, the Zeeman Effect is commonly studied in atomic gases using water-cooled electromagnets and Fabry-Perot etalons. To that end, normal Zeeman splitting in H/D plasmas has been detected [1-2] using long spectrometers in plasma fusion devices operating with strong superconducting magnets. Alternatively, we have developed a method, using a permanent magnet apparatus, to study the Paschen-Back limit in He [3]. This approach was further improved to allow for stronger magnetic fields and combined with a high-resolution spectroscopic system [4]. It was subsequently applied to study anomalous Zeeman splitting in excited neutral gases [5]. In this work, we report our method's extension to the spectrum of ionized argon, allowing students to study the splitting of the ArII emission lines which were originally investigated by Pieter Zeeman and his colleagues [6].