Overview of the Basic Plasma Science Facility: the physics of waves relevant to space plasmas

The Basic Plasma Science Facility (BaPSF) at UCLA is a US national user facility for studies of fundamental processes in magnetized plasmas. The centerpiece of the facility is the Large Plasma Device (LAPD), a 20m long, magnetized linear plasma device~\cite{lapd}. This LAPD has been utilized to study a number of fundamental processes, including: collisionless shocks~\cite{shocks}, dispersion and damping of kinetic and inertial Alfv\'{e}n waves~\cite{iowa}, flux ropes and magnetic reconnection~\cite{fluxr}, three-wave interactions and parametric instabilities of Alfv\'{e}n waves~\cite{3w}, turbulence and transport~\cite{schaff} and interactions of energetic ions and electrons with plasma waves~\cite{chirp}. An overview of research using the facility will be given, followed by a more detailed discussion of studies of the nonlinear physics of Alfv\'{e}n waves~\cite{decay} and the propagation of Alfv\'{e}n waves in multi-ion plasmas. Recent experiments have resulted in the first laboratory observation of the parametric instability of shear Alfv\'{e}n waves. Shear waves with sufficiently high $\omega/\Omega_{\rm c,i}$ ($> 0.6$) and above a threshold wave amplitude are observed to decay into co-propagating daughter waves; one a shear Alfv\'{e}n wave and the other a low-frequency quasimode. The observed process is similar to the modulational decay instability. The second study has focused on the propagation of shear Alfvén waves in plasmas with two ion species, for example He and Ne. Two distinct propagation bands are observed, bounded by $\omega < \Omega_{\rm Ne}$ and $\omega_{ii} < \omega < \Omega_{\rm He}$, where $\omega_{ii}$ is the ion-ion hybrid frequency~\cite{vincena}. The polarization properties of these waves have been documented, showing that in the the lower band the waves are linearly polarized, while in the upper band the waves are primarily left-hand polarized.

\begin{thebibliography}{99} \bibitem{lapd} W. Gekelman, et al., Review of Scientific Instruments {\bf 87}, 025105 (2016). \bibitem{shocks} A.S. Bondarenko, et al., Nature Physics {\bfseries 13}, 573 (2017). \bibitem{iowa} C.A. Kletzing, et al., Phys. Rev. Lett. {\bfseries 104}, 095001 (2010). \bibitem{fluxr} W. Gekelman, et al., Phys. Rev. Lett. {\bfseries 116}, 235101 (2016). \bibitem{3w} G. Howes, et al., Phys. Rev. Lett. {\bfseries 109}, 255001 (2012). \bibitem{schaff} D.A. Schaffner, et al., Phys. Rev. Lett. {\bfseries 109}, 135002 (2012). \bibitem{chirp} B. Van Compernolle, et al., Phys. Rev. Lett. {\bfseries 114}, 245002 (2015). \bibitem{decay} S. Dorfman and T.A. Carter, Phys. Rev. Lett. {\bfseries 116}, 195002 (2016). \bibitem{vincena} S. Vincena, et al., Geophys. Rev. Lett. {\bfseries 38}, L11101 (2011)

\end{thebibliography}