Time domain structures in magnetic flux rope experiments

Time Domain Structures (TDS) are narrow, intense spikes that appear in the electric potential/field measurements of numerous space observations and laboratory experiments. They are believed to be associated with end state of turbulence and may have connections to the chaotic behavior of Lorentzian spikes. In an ongoing investigation at UCLA, TDS have been observed near the surface of two magnetized flux ropes produced within the LArge Plasma Device (LAPD). Two 11 m long kink-unstable flux ropes were created by a lanthanum hexaboride (LaB6) source and are encapsulated by a 18 m long background plasma produced by a barium oxide (BaO) cathode. A preliminary analysis of the TDS suggest that they may be associated with the motion of the ropes and it appears that they emanate from the reconnection region between the ropes. In addition, these structures appear to have Lorentzian character (an indicator of chaotic behavior) and can couple to the kinking of the ropes when more power is delivered to the ropes. As the ropes become more chaotic under higher magnetic guide fields (~1kG), the effect of this on the TDS will be explored.