Friedrich Paschen

Louis Carl Heinrich Friedrich Paschen was a German physicist, known for his work on electrical discharges. He is also known for the Paschen series, a series of hydrogen spectral lines in the infrared region that he first observed in 1908. He established the now widely used Paschen curve in his article "Über die zum Funkenübergang in Luft, Wasserstoff und Kohlensäure bei verschiedenen Drücken erforderliche Potentialdifferenz". He is known for the Paschen-Back effect, which is the Zeeman effect's becoming non-linear at high magnetic field. He helped explain the hollow cathode effect in 1916.