Laboratory Experiments of Alfvén Wave Interactions through the Transition from the MHD to the Kinetic Range*

Turbulence is ubiquitous throughout different space plasma environments, facilitating the cascade of energy down to smaller and smaller length scales.  That said, the different parameter regimes at which these plasmas exist have a significant effect on the way the cascade develops.  Though in-situ measurements can provide a wealth of knowledge about the properties of space turbulence, they are limited by their spatial extent relative to the plasma environment and their reproducibility.  Laboratory plasma experiments like those run on the LArge Plasma Device (LAPD) at the University of California-Los Angeles can provide insight complementary to satellite data.  The space plasma turbulence group at Queen Mary University of London (QMUL) has run Alfvén wave experiments on LAPD studying weak and strong interactions at a range of k_⊥ρ_s values, from very small (MHD limit) up to order unity (kinetic limit).  The change in the properties of the drive waves and their interaction products between these limits has been quantified via detailed measurements of magnetic and electric field fluctuations in multiple different counter-propagating wave configurations.  Further data runs allowed for an analysis of the residual energy- and cross helicity-dependent properties of the interactions.  With this experimental setup, the fundamental physics of the three-wave interaction can be studied in detail while minimizing the impact of other solar wind phenomena.