Showing papers by "Mary K. Hudson published in 1992"
TL;DR: In this paper, the authors examined the theoretical properties of linear ion cyclotron waves propagating in the magnetosphere at arbitrary angles to the background magnetic field and found that in some cases the linear wave growth of modes with oblique propagation can dominate that of the parallel propagating electromagnetic IC wave.
Abstract: The study examines the theoretical properties of linear ion cyclotron waves propagating in the magnetosphere at arbitrary angles to the background magnetic field. It is found that in some cases the linear wave growth of modes with oblique propagation can dominate that of the parallel propagating electromagnetic ion cyclotron (EMIC) wave. The growth rate of the loss-cone-driven mode depends strongly on the depth of the loss cone. A simple analytical theory which explains the scaling of the growth rate of the oblique mode with respect to various parameters is presented. The loss-cone-driven mode is an electromagnetic mode which is preferentially nearly linearly polarized. The wave field which results from the oblique mode in its perferentially nearly linearly polarized form are nearly perpendicular to B0 and are such that they may be difficult to distinguish from those of a linearly polarized parallel propgating EMIC wave.
59 citations
TL;DR: In this article, the formation of acoustic double layers in the presence of two ion species is examined. But the results are restricted to the case of a single ion component and do not account for the effect of having two ion components.
Abstract: Particle simulation in a one-dimensional bounded system is used to examine the formation of acoustic double layers in the presence of two ion species. Double-layer formation depends critically on the details of the distribution functions of the supporting ion populations, and their relative drifts with respect to the electrons. The effect of having two ion components, an H/sup +/ and an O/sup +/ beam, on double-layer evolution from ion acoustic turbulence driven by an electron drift relative to the H/sup +/ beam of approximately=0.5u/sub e/, where uu/sub e/ is the electron thermal speed, is examined. The ratio of ion drifts is taken to be consistent with acceleration by a quasi-static auroral potential drop (i.e. V/sub H//V/sub O/= square root M/sub O//M/sub H/=4.0). Acoustic double layers form in either ion species on the time scale tau approximately=100 omega /sub ps//sup -1/, where omega /sub ps/ is the ion plasma frequency for species 's' and s=H or O, and for drifts relative to the electrons lower than that required for double layer formation in simulations of single ion component plasma. >
12 citations
TL;DR: In this paper, a model of electron distributions which is consistent with observations is used for analysis of the excited waves, their dependence upon plasma parameters, and the time scales of the saturation processes.