Hybrid simulation of Alfven wave parametric decay instability in a laboratory relevant plasma

Large-amplitude Alfven waves are subject to parametric decays, which can have important consequences in space, astrophysical, and fusion plasmas. Although the Alfven wave parametric decay instability (PDI) was predicted decades ago, observational evidence is limited, stimulating considerable interest in laboratory demonstration of the instability and associated numerical modeling. Here, we report an important step toward direct hybrid simulation of the Alfven wave PDI in a laboratory plasma, using antenna-like wave injection of a circularly polarized wave and realistic wave-plasma parameters. Considering collisionless damping, we identify the threshold Alfven wave amplitudes and frequencies required for triggering the instability. These threshold behaviors are corroborated by simple theoretical analysis, considering the balance between PDI growth and ion Landau damping and PDI development in a bounded plasma. Other effects not included in the present model such as finite transverse wave scale and ion-neutral collisions are briefly discussed. These hybrid simulations promise to be a useful tool for investigating laboratory Alfven wave dynamics and may provide guidance for future laboratory demonstration of the PDI process. Published under an exclusive license by AIP Publishing.