Investigating Magnetospheric Whistler-Mode Chorus Features using SPSC Laboratory Experiments

Wave-particle interactions between electrons and whistler-mode waves play an important role in the dynamics of the outer radiation belt. This work uses NRL's Space Physics Simulation Chamber (SPSC) to explore the kinetic processes responsible for the amplitude growth, chirped frequency, and Ω_ce/2 power gap common to whistler-mode chorus. Recent SPSC experiments with whistler-mode waves and a counterpropagating electron beam produced nonlinear wave growth and triggered chirped emission of whistler-mode waves. WIth these experimnts, we aim to add measurements of the electron velocity distribution using an energy analyzer and a wave absorption diagnostic. Additional features of the SPSC include the ability to create uniform or flared background magnetic field to study the effect of inhomogeneities on whistler-mode chorus and an electron beam with steerable pitch angle. We will present results exploring optimal conditions leading to wave growth and triggered emissions.