High fidelity simulations of ion trajectories in miniature ion traps using the boundary-element method

In this paper we present numerical modeling results for endcap and linear ion traps, used for experiments at the National Physical Laboratory in the UK and Innsbruck University respectively. The secular frequencies for Strontium-88 and Calcium-40 ions were calculated from ion trajectories, simulated using boundary-element and finite-difference numerical methods. The results were compared against experimental measurements. Both numerical methods showed high accuracy with boundary-element method being more accurate. Such simulations can be useful tools for designing new traps and trap arrays. They can also be used for obtaining precise trapping parameters for desired ion control when no analytical approach is possible as well as for investigating the ion heating rates due to thermal electronic noise.Comment: 6 pages, 5 figures, changes made to the text according to the editor's and referee's comment

Effects of varying magnetosheath flow and dissipation on the two-dimensional reconnection structure at the magnetopause

The stationary Riemann problem including dissipation in form of resistivity and viscosity for the reconnection structure at the dayside magnetopause is considered. Including tangential velocity shear and gradients across the complete reconnection structure from the magnetosheath side into the magnetosphere, it is shown how dissipation affects the thickness of the intermediate shock wave in the vicinity of a reconnection site. We present how plasma flow structure undergoes a significant change for a nonzero uniform plasma velocity and velocity gradient. It is also shown how the reconnection rate changes and leads to a cutoff when the velocity becomes Alfvénic.Validerad; 2009; 20090519 (lgwe

Low-temperature SIMS mass spectra of diethyl ether

For the first time a secondary ion mass spectrum of diethyl ether was obtained at low temperature. The spectrum recording became possible by carefully selecting the range of experimental conditions for the production of a cluster-type spectrum. This range is specified by the threshold for spectrum appearance above the melting temperature of the frozen sample and a fairly short time span of existence of the liquid estimated as only a few minutes. The latter necessitates rather rapid spectrum detection. In practice, about 1 min was available for recording of the cluster-type spectra. The secondary emission mass spectrum of diethyl ether appeared to be rich in peaks: along with abundant protonated clusters M-n . H+ (n = 1-12), unusually intense [M-n-H](+) and weaker M-n(+.) peaks were present accompanied by several sets of fragmented clusters, [M-n-15](+), [M-n-29](+), [M-n-27](+), [M-n- 45](+), and monohydrates, M-n . H2O . H+. The analysis of all the peaks showed that the pattern of fragment clusters is qualitatively similar to the pattern of fragmentation of the diethyl ether molecular ion under high-energy electron impact. The general features of the behaviour of diethyl ether under low-temperature mass spectrometric conditions were similar to those observed earlier for some other organic solvents