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[en] Analytical and numerical work is used in tandem to address the problem of turbulent transport of energetic ions in magnetized plasmas. It is shown that orbit averaging is not valid under rather generic conditions, and that perpendicular decorrelation effects lead to a slow 1/E decay of the electrostatic particle diffusivity of beam ions, while the respective magnetic quantity is even independent of the particle energy E
[en] It is shown that there exist two types of m = n = 1 fishbone modes with frequencies significantly exceeding the frequency of the conventional fishbone instability. One of them is the resonance continuum mode (RCM), and the other is the non-resonance gap mode (NGM). They are associated with the trapped energetic ions and arise due to plasma compressibility. The spatial structure of the RCM may differ considerably from the rigid kink displacement inherent in the conventional fishbone mode.
[en] A possibility to improve the confinement of energetic ions in stellarators by transforming trapped particles into passing ones using RF waves is investigated. It is concluded that waves with frequencies around the ion gyrofrequency or lower can, in principle, be used for this purpose if certain requirements are satisfied. The suitability of the W7-X ICRH system is considered, and other means for achieving fast-ion confinement are discussed. (paper)
[en] New energetic particle mode instabilities of fishbone type are predicted. The considered instabilities are driven by the circulating energetic ions. They can arise in plasmas of tokamaks and spherical tori with weak magnetic shear in the wide core region and strong shear at the periphery, provided that the central safety factor is close to the ratio m/n, where m and n are the poloidal mode number and toroidal mode number, respectively. The instability with m = n = 1 has interchange-like spatial structure, whereas the structure of instabilities with m/n > 1 is similar to that of the infernal MHD mode (except for the region in vicinity of the local Alfven resonance)
[en] Different experimental schemes for investigation of warm dense matter produced with intense energetic ion beams are presented. The described target configurations allow direct measurements of thermophysical and transport properties of warm dense matter without hydrodynamic recalculations. The presented experiments will be realized at the current GSI synchrotron SIS-18 and the future FAIR facility in the framework of the WDM-collaboration.
[en] Recently, Schwadron and McComas discussed the possibility of inner source pickup particles originating from the ionization of energetic neutral atoms (ENAs), based on new data from the IBEX mission. This proposition has some interesting features, namely, it might be able to explain why inner source pickup ions (PUIs) have a composition resembling solar abundances and show no indication of overabundance of refractory elements, although this should be expected, if the conventional explanation of solar wind-dust interaction for the origin of this heliospheric component were correct. In this Letter, we explore further consequences for ENA-related PUIs and investigate their velocity distributions. We conclude that this model will not reproduce the observed velocity distributions of inner source PUIs and point out a substantial deviation in their composition. However, it seems likely that the ionization of ENAs as observed with IBEX could contribute a significant amount of heliospheric suprathermal tail ions. Some possible consequences of our investigation for heliospheric particle populations are briefly discussed.
[en] A new ion identification method for ΔE-E telescopes is presented. The method works by counting data points under ΔE(E) curves on ΔE-E diagrams. These curves are obtained by simulating the telescope response to a flux of energetic ions. The method is checked against three published methods applied to several experimental data sets
[en] Ion range is one of the most important considerations in describing ion-solid interactions. When an energetic ion penetrates a solid, it undergoes electronic and nuclear stopping in the target. In the beginning of the slowing-down process at high energies, the ion is slowed down mainly by electronic stopping, and it moves almost in a straight path. As the ion energy decreases, the probability of collisions with nuclei increases and the nuclear stopping finally dominates the slowing-down process. During the collision processes, target atoms (target recoils), which receive significant recoiling energies from the ion, will be removed from their lattice positions and produce a cascade of further collisions in the target.
[en] The internal behavior of fast ions interacting with magnetohydrodynamic bursts excited by energetic ions has been experimentally investigated in the compact helical system. The resonant convective oscillation of fast ions was identified inside the last closed-flux surface during an energetic-particle mode (EPM) burst. The phase difference between the fast-ion oscillation and the EPM, indicating the coupling strength between them, remains a certain value during the EPM burst and drives an anomalous transport of fast ions