Alfvén waves are ubiquitous in space plasmas and are the means by which information about changing currents and magnetic fields are communicated. Shear Alfvén waves radiated from sources with cross-field scale size of the order of the electron inertial length, δ=c/ωpe, have properties which differ considerably from planar magneto-hydrodynamic waves. Currents of cross-field size δ are common in space plasmas. A series of experiments in the large plasma device (LAPD) at UCLA is presented which illustrates that waves generated by small scale fluctuating currents radiate across magnetic field lines and are associated with complex three-dimensional currents. Waves generated by two sources are observed to constructively interfere to produce large magnetic fields in spatial regions away from source field lines. Volume data sets will be presented and discussed in the light of space plasma applications.
Guided propagation of Alfven waves in a toroidal plasma