The energization of ions in a dynamic system containing two colliding magnetic flux ropes is investigated in an experimental study presented in this dissertation. Two kink-unstable flux ropes on the Large Plasma Device (LAPD) are made to collide in order to trigger magnetic reconnection, a process in which magnetic energy stored in the fields is dissipated into thermal and kinetic energy that is picked up by surrounding ions. The local energy distribution of the ions is measured by a four-grid ion retarding field energy analyzer that was constructed specifically for this study. The average energy ⟨2E⟩, a quantity equivalent to the Maxwellian temperature for non-Maxwellian distribution functions, was plotted as a function of time for two different flux rope conditions. In both cases, ⟨2E⟩ spikes indicated the presence of an ion beam with a sub-Alfv�nic drift velocity of 9 to 15�eV. The beam does not appear to be heated and the ion temperature of the ropes is estimated to be between 4 to 6�eV. This is found to be consistent with a spectrometer’s line-of-sight, volume-averaged measurement involving Doppler broadening of the 320.3�nm He�II spectral line. Using polar plots as a visualization tool for the two-dimensional ion distribution function, the beam appears to travel primarily in the +z direction along the magnetic field and out of the reconnection plane. The presence of the beam is also correlated with magnetic reconnection events that were identified by plotting line contour planes of the magnetic vector potential A_(z). This means that the ions are likely to be accelerated by -dA_(z)/dt, the inductive electric fields created during magnetic reconnection. Furthermore, the energy density produced by the induced electric fields (0.5�J/m�) is comparable to the energy per unit volume required to heat the ions from 6 to 10�eV (0.3�J/m�) after accounting for a less than 50% efficiency of energy transferred to the ions. Overall, the evidence presented in this study strongly suggests that the ions in the beam are produced by magnetic reconnection. To the author’s knowledge, this is the first experimental observation of a field-aligned ion beam generated in a reconnection experiment.

Magnetic helicity, a measure of the linkage of magnetic field lines, has long been used in the contexts of astrophysical and experimental plasmas because, for highly conductive plasmas, it is a conserved quantity. In this experimental study, the dynamics of two magnetic flux ropes and the magnetic reconnection that occurs between them is used as a proving ground for helicity conservation theory. A magnetic flux rope is a twisted bundle of magnetic field lines that is ubiquitous in space and solar plasmas. Two magnetic flux ropes are created in the Large Plasma Device (LAPD) using a lanthanum hexaboride (LaB6) cathode that injects current along a background, magnetic field. The flux ropes are kink unstable, causing them to collide. As they collide, the field lines diverge, and a quasi-separatrix layer (QSL) forms. The QSL is an indicator of magnetic field line reconnection. Helicity conservation is examined inside the QSL. Two types of helicity are considered: relative magnetic helicity, which is a standard formulation, and relative canonical helicity, an extension. Three-dimensional measurements of plasma density (ne), electron temperature (Te), plasma potential (ϕp), the magnetic field (B), and ion flow (vflow) are required to evaluate each terms that appear in the extended formulation of helicity. In the magnetohydrodynamic (MHD) limit, the transport of relative magnetic helicity and the dissipation of relative magnetic helicity do not balance. Using relative canonical helicity, the dissipation of relative canonical helicity is balanced by the transport of relative canonical helicity into the QSL – such that the temporal derivative of the quantity is zero. The electrostatic field is the key term that balances helicity. It is ignored in the standard model of helicity. In this experiment, the electrostatic component of the electric field is large compared to the induced electric field produced by reconnection; and therefore, it should not be ignored in other circumstances.