Authors: Mel Abler (Space Science Institute), Seth Dorfman (Space Science Institute), Christopher HK Chen (Queen Mary University of London)

In the MHD inertial range (scales larger than ion-kinetic scales) turbulent fluctuations in the solar wind are often Alfvénic in character, meaning that their magnetic and flow velocity fluctuations are proportional to each other and predominantly perpendicular to the background magnetic field. However, observations of the solar wind have shown that there is a significant difference in the energy in velocity fluctuations and the energy in normalized magnetic field fluctuations. This difference, called the residual energy, should be zero for linear Alfvén waves, but is consistently observed to be negative in the solar wind, with magnetic fluctuations dominating. This work investigates the energy partition in strong three-wave interactions as a building block of the turbulent cascade through an experimental campaign on the LArge Plasma Device (LAPD) in an MHD-like regime relevant to the solar wind. In these experiments, primary (driven) modes are launched from antennas, and the spectrum of secondary modes generated by the strong three-wave interaction is observed. The residual energy present in both the primary and secondary modes is measured using multiple techniques to shed light on how these interactions generate residual energy.

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