Drift-free magnetic geometries in adiabatic

A class of two-dimensional drift-free fields, somewhat resembling the configuration found in the geomagnetic tail, is described; several proofs of the drift-free property are given, including some that suggest that the property of vanishing net drift might extend to nonadiabatic orbits. A general criterion for identifying drift-free fields was developed, and a case of motion in a nearly drift-free field was also investigated. The theory was applied to the plasma sheet in the earth's magnetotail, and observational evidence is presented suggesting that the magnetic field there does approach a drift-free configuration

Simulation of electrostatic ion instabilities in the presence of parallel currents and transverse electric fields

A spatially two-dimensional electrostatic PIC simulation code was used to study the stability of a plasma equilibrium characterized by a localized transverse dc electric field and a field-aligned drift for L is much less than Lx, where Lx is the simulation length in the x direction and L is the scale length associated with the dc electric field. It is found that the dc electric field and the field-aligned current can together play a synergistic role to enable the excitation of electrostatic waves even when the threshold values of the field aligned drift and the E x B drift are individually subcritical. The simulation results show that the growing ion waves are associated with small vortices in the linear stage, which evolve to the nonlinear stage dominated by larger vortices with lower frequencies

Properties of the spokes in coaxial and parallel - Plate plasma accelerator

Photographic, magnetic, and spectroscopic study of vortex spokes in coaxial and parallel-plate plasma accelerator

Anomalous Resistivity in Magnetosphere-Ionosphere Current Systems: The Role of Ion Cyclotron Turbulence

Field aligned currents flowing between the auroral zone topside ionosphere and the magnetosphere excite the electrostatic ion cyclotron instability when the electron drift velocity exceeds-1/31 VTe (H+ mode). Typically, this condition is satisfied at altitudes \u3e1000km. We have made numerical estimates of anomalous resistivity due to ion cyclotron turbulence as a function of altitude in such current systems. In order to arrive at these estimates we have assessed the role played by electron-ion collisions, spatial effects such as convection of wate energy, and various competing nonlinear saturation mechanisms (Quasi-linear plateau formation, ion resonance broadening, nonlinear ion Landau damping, etc.) in the ionosphere-magnetosphere environment