The Induced Magnetospheres of Mars, Venus, and Titan

This article summarizes and aims at comparing the main features of the induced magnetospheres of Mars, Venus and Titan. All three objects form a well-defined induced magnetosphere (IM) and magnetotail as a consequence of the interaction of an external wind of plasma with the ionosphere and the exosphere of these objects. In all three, photoionization seems to be the most important ionization process. In all three, the IM displays a clear outer boundary characterized by an enhancement of magnetic field draping and massloading, along with a change in the plasma composition, a decrease in the plasma temperature, a deflection of the external flow, and, at least for Mars and Titan, an increase of the total density. Also, their magnetotail geometries follow the orientation of the upstream magnetic field and flow velocity under quasi-steady conditions. Exceptions to this are fossil fields observed at Titan and the near Mars regions where crustal fields dominate the magnetic topology. Magnetotails also concentrate the escaping plasma flux from these three objects and similar acceleration mechanisms are thought to be at work. In the case of Mars and Titan, global reconfiguration of the magnetic field topology (reconnection with the crustal sources and exits into Saturn??s magnetosheath, respectively) may lead to important losses of plasma. Finally, an ionospheric boundary related to local photoelectron signals may be, in the absence of other sources of pressure (crustal fields) a signature of the ultimate boundary to the external flow.     

Reactant jetting in unstable detonation

We note the common existence of a supersonic jet structure locally embedded within a surrounding transonic flow field in the hitherto unrelated phenomena of unstable gaseous detonation and hypervelocity blunt body shock wave interaction. Extending prior results that demonstrate the consequences of reduced endothermic reaction rate for the supersonic jet fluid in the blunt body case, we provide an explanation for observations of locally reduced OH PLIF signal in images of the keystone reaction zone structure of weakly unstable detonations. Modeling these flow features as exothermically reacting jets with similarly reduced reaction rates, we demonstrate a mechanism for jetting of bulk pockets of unreacted fluid with potentially differing kinetic pathways into the region behind the primary detonation front of strongly unstable mixtures. We examine the impact of mono-atomic and diatomic diluents on transverse structure. The results yield insight into the mechanisms of transition and characteristic features of both weakly and strongly unstable mixtures.     

Synthesis of electrode system and simulation of ion-marking sensor for aerodynamic angle and airspeed measurement

A functional scheme, primary informative signals, a method of electrode system structural parameters synthesis and evaluation of a systematic error of the ion-marking sensor for aerodynamic angle and airspeed measurement are the focus of this paper.     

How Galactic Cosmic Ray models affect the estimation of radiation exposure in space

The radiation environment in space is a major concern for human spaceflight because of the adverse effects of high levels of radiation on astronauts’ health. Therefore, it is essential to perform radiation risk assessments already during the concept studies of a manned mission. Galactic Cosmic Rays (GCR) have been identified to be one of the primary sources of radiation exposure in space.     

Semi-automatic determination of the Azores Current axis using satellite altimetry: Application to the study of the current variability during 1995–2006

Satellite altimetry has been widely used to study the variability of the ocean currents such as the Azores Current (AzC) in the North Atlantic. Most analyses are performed over the region that encloses the current, thus being somehow affected by other oceanographic signals, e.g., eddies. In this study, a new approach for extracting the axis of a zonal current solely based on satellite altimetry is presented. This is a semi-automatic procedure that searches for the maximum values of the gradient of absolute dynamic topography (ADT), using the geostrophic velocity as auxiliary information. The advantage of this approach is to allow the analyses to be performed over a buffer centered on the current axis instead of using a wider region. It is here applied to the AzC for the period June 1995–October 2006.