Identifying the Structure of Whistler Wave Excitation in a Laboratory Plasma
Tuesday, 15 December 2015
Poster Hall (Moscone South)
The excitation of whistler waves is studied with a gyrating electron beam injected into a cold plasma in a controlled laboratory environment. The mode structure of whistler wave excitation is identified using a phase-correlation technique. It is shown that whistler waves are excited through Landau resonance, cyclotron resonance and anomalous cyclotron resonance. The dominant wave mode excited through cyclotron resonance is nearly parallel-propagating, whereas wave modes excited through Landau resonance and anomalous cyclotron resonance can propagate close to the resonance cone. Linear analysis on wave growth rate captures the major resonance modes in the experiment. The results have implications for the generation process of whistler waves in the Earth's inner magnetosphere.