title: Excitation of Chirping Whistler Waves in a Laboratory Plasma.
abstract: Whistler mode chorus emissions with a characteristic frequency chirp are important magnetospheric waves, responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Here, we report on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced using a beam of energetic electrons launched into a cold plasma. Frequency chirps are only observed for a narrow range of plasma and beam parameters, and show a strong dependence on beam density, plasma density, and magnetic field gradient. Broadband whistler waves similar to magnetospheric hiss are also observed, and the parameter ranges for each emission are quantified.
authors.affiliation: Department of Physics, University of California, Los Angeles, California 90095, USA.
authors.forename: B
authors.initials: B
authors.lastname: Van Compernolle
authors.affiliation: Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California 90095, USA.
authors.forename: X
authors.initials: X
authors.lastname: An
authors.affiliation: Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California 90095, USA.
authors.forename: J
authors.initials: J
authors.lastname: Bortnik
authors.affiliation: Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California 90095, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Thorne
authors.affiliation: Department of Physics, University of California, Los Angeles, California 90095, USA.
authors.forename: P
authors.initials: P
authors.lastname: Pribyl
authors.affiliation: Department of Physics, University of California, Los Angeles, California 90095, USA.
authors.forename: W
authors.initials: W
authors.lastname: Gekelman